Turbo-molecular pump for mass spectrometer
阅读说明:本技术 用于质谱仪的涡轮分子泵 (Turbo-molecular pump for mass spectrometer ) 是由 约亨·弗兰岑 乌尔斯·斯坦纳 于 2019-08-14 设计创作,主要内容包括:本发明涉及能够实现高泵速的涡轮分子泵。本发明提出使用一个或多个笼状转子级来优化具有低气流和低极限压力的真空系统上的泵速。这允许较小的电动机以及较小的整体形状因子,并且特别适用于紧凑型质谱仪和台式质谱仪。(The present invention relates to a turbomolecular pump capable of realizing a high pumping speed. The present invention proposes the use of one or more caged rotor stages to optimize pump speed on vacuum systems with low gas flow and low ultimate pressure. This allows for smaller motors and smaller overall form factors, and is particularly suitable for compact mass spectrometers and bench top mass spectrometers.)
1. A turbomolecular pump comprising a fixed frame structure and at least one rotor stage at a low pressure input region, wherein a rotor in the at least one rotor stage rotates relative to the fixed frame structure during operation, and the rotor has a central shaft receiving member from which a first rotor blade section extends substantially radially outward and is connected to a second rotor blade section which extends substantially coaxially with and along the central shaft receiving member towards a high pressure output region, the first and second rotor blade sections deflecting gaseous matter substantially in a near axial and radially inward direction during operation.
2. The turbomolecular pump of claim 1, wherein the rotor blades in the first rotor blade section are inclined with respect to a first plane perpendicular to the central shaft receiving member, and the rotor blades in the second rotor blade section are inclined with respect to an envelope profile of the substantially hollow cylindrical shape generated by the second rotor blade section.
3. The turbomolecular pump of claim 1, further comprising a third rotor blade section extending substantially radially outward from the central shaft receiving member and connected to the second rotor blade section at a location between the low pressure input region and the high pressure output region to enhance mechanical stability, wherein during operation, the third rotor blade section deflects gaseous matter substantially in a near-axial direction.
4. The turbomolecular pump of claim 3, wherein the rotor blades in the third rotor blade section are inclined with respect to a second plane perpendicular to the central shaft receiving member.
5. The turbomolecular pump of claim 1, wherein the number of rotor blades in at least one of the first, second and third rotor blade parts is odd to reduce resonant vibrations.
6. The turbomolecular pump of claim 1, wherein adjacent rotor blades in at least one of the first, second and third rotor blade sections substantially overlap each other to prevent gaseous matter that has entered inside from escaping or otherwise exiting in a direction other than towards the high pressure output region.
7. The turbomolecular pump of claim 1, further comprising an annular support structure connected with a distal end of a rotor blade in the second rotor blade section to enhance mechanical stability.
8. The turbomolecular pump of claim 1, wherein a rotor blade in the second rotor blade section comprises a rounded edge at a connection point with a rotor blade in the first rotor blade section.
9. The turbomolecular pump of claim 1, wherein the first rotor blade section transitions into the second rotor blade section.
10. The turbomolecular pump of claim 1, wherein the proximal axial extension of the second rotor blade section is equal to or greater than the radial extension of the first rotor blade section.
11. The turbomolecular pump of claim 1, wherein the central shaft receiving member comprises a hollow receptacle for accommodating a drive shaft, which can rotate the central shaft receiving member.
12. The turbomolecular pump of claim 1, wherein the central shaft receiving member flares, at least in a partial section, from the high pressure output region to the low pressure input region to impart additional momentum in a direction towards the high pressure output region to the gaseous matter deflected from the second rotor blade portions in a generally radially inward direction.
13. The turbomolecular pump of claim 1, wherein rotor blades in the second rotor blade section are helically twisted along the substantially hollow cylindrical envelope profile generated by the second rotor blade section to deflect the gaseous substance from the second rotor blade section substantially in a proximal-axial and radially-inward direction.
14. A turbomolecular pump according to claim 1, wherein the rotor in the at least one rotor stage is made of a stable metal such as aluminium, magnesium, titanium or an alloy of said stable metals.
15. The turbomolecular pump of claim 1, wherein in a multiport configuration, the turbomolecular pump further comprises a second rotor stage located at a position spaced apart from the low pressure input region, the second rotor stage having a similar configuration to the at least one rotor stage located at the low pressure input region.
16. A mass spectrometer, comprising:
-a receiver having at least two adjacent compartments maintained at a pressure substantially below ambient atmospheric pressure during operation; and
-the multi-port configured turbomolecular pump of claim 15, mounted at the at least two adjacent compartments, such that the second rotor blade section substantially protrudes into a first of the at least two adjacent compartments, and the second rotor stage is fluidly connected with a second of the at least two adjacent compartments.
17. A mass spectrometer, comprising:
-a receiver having at least one compartment, the at least one compartment being maintained at a pressure substantially below ambient atmospheric pressure during operation; and
-a turbomolecular pump according to claim 1, mounted at the at least one compartment such that the second rotor blade sections substantially protrude into the at least one compartment.
18. The mass spectrometer of claim 17, wherein the at least one compartment contains at least one mass analyzer or at least one gas source, and the second rotor blade section protrudes directly exposed to gaseous species escaping or otherwise exiting the at least one mass analyzer and emanating from the at least one gas source, respectively.
19. The mass spectrometer of claim 17, wherein the at least one compartment comprises at least one of a time-of-flight drift tube, a golden den type mass analyzer, a 2D or 3D ion trap, a mass filter, and an ion cyclotron resonance cell.
Technical Field
The present invention relates to a turbomolecular pump capable of realizing a high pumping speed. The present invention proposes to optionally use one or more novel caged rotor stages (rotor stages) in addition to the conventional rotor stages commonly used in the art to optimize the pump speed of a vacuum system with low gas flow and low ultimate pressure. This allows for smaller motors and smaller overall form factors, and is particularly suitable for compact Mass Spectrometers (MS) and bench top mass spectrometers.
Background
Conventional turbomolecular pumps typically consist of a low pressure input stage and a high pressure exhaust section. The low-voltage input stage consists of a stack of rotors, each having a plurality of angled vanes, mounted in a tubular housing, rotating at very high tangential speeds. Gas molecules that are impacted by the underside of the angled vanes move with momentum in the direction of the high pressure exhaust section.
The low-voltage input stage therefore consists of a stacked disk-shaped turbine rotor with radially extending rotor blades. Typically, there is a non-rotating stator with opposing angled radial vanes between each rotor. The pump speed of a turbomolecular pump is given by the blade diameter and the rotational speed (revolutions per minute, RPM) of the turbine rotor blades. The rotational speed is limited by the strength of the blade material, which must withstand centrifugal forces and be heated to a temperature resulting from the total gas load to be pumped.
Experience has shown that the material strength of the vanes of currently commercially available turbomolecular pumps has been optimized and cannot be improved significantly. In many cases, for example in mass spectrometers, the gas load is minimal. In such analyzers with long ion trajectories, the ion mean free path (mean propagation distance between two collisions with other gaseous species) should be kept as long as possible, which means that the absolute end pressure (end pressure) must be as low as possible. To obtain a mean free path of more than 10 cm, less than 10 is required-5Torr (-1.3X 10)-3Pascal) pressure. In many high resolution MS systems (e.g., time-of-flight, ion cyclotron resonance cell) and from Thermo Fisher Scientific
(orbitrap)), ions can stay in the analyzer for seconds, which requires a mean free path of more than one meter. In this system, less than 10 is required-7Torr (-1.3X 10)-5Pascal) pressure, e.g. up to 10-11Torr (-1.3X 10)-9Pascal).To achieve this low end pressure in the presence of gas loading, the pump speed needs to be high, which currently requires larger pump sizes with larger rotor diameters. This in turn requires a larger vacuum chamber, which in turn increases the overall system size and greatly increases cost. The gas load of the MS system comes primarily from the ion source and some surface outgassing. In some cases, additional gas is introduced into the collision cell of the MS system to cool the ions or fragment the molecular ions, the gas eventually leaking and thus increasing the gas load of other parts of the vacuum receiver of the mass spectrometer.
In many cases, mass spectrometers include an inlet and an ion source with a high gas load. If these regions can operate at higher pressures, a multi-port turbo-molecular pump can be used. In this case, the interstage opening is placed at the appropriate pressure level of the pump. The height and width of these openings are selected to support sufficient airflow. To optimize the gas flow, the rotor and stator may be removed in these sections.
Turbomolecular pumps also typically contain so-called Holweck stages, which are of the type with a drag compression stage (drag compression stage) having a radial flow component. In essence, the Holweck stage is a rotating helical rotor that rotates in a stationary cylinder. This creates a rotating channel towards the higher pressure region. Surface friction is used to move molecules along the channel. Another method of drag stage involves rotating a disk with or without grooves in the disk (so-called Gator stage). This will generate a radial flow component. However, all of these known drag stages are located close to the high pressure exhaust section, rather than at the low pressure end of the volume to be evacuated.
Disclosure of Invention
The invention relates to a turbomolecular pump comprising a fixed (static) frame structure and at least one rotor stage at the low-pressure inlet region, wherein the rotor in at least one rotor stage rotates relative to the stationary frame structure during operation, and the rotor has a central shaft receiving member, which may comprise a hollow receptacle for receiving a drive shaft, which is capable of rotating the central shaft receiving member, the first rotor blade section extending generally radially outwardly from the central shaft receiving member and being connected to the second rotor blade section, for example (smoothly) into a second rotor blade section, which extends substantially coaxially (and along) the central shaft receiving member towards the high pressure output region, wherein during operation, the first and second rotor blade sections deflect gaseous matter generally in an axially and radially inward direction.
The basic idea of the invention is to supplement the conventional only radially extending rotor blades in the first rotor stage at the low pressure input region with a cage having a set of additional near-axis rotor blade sections (sub blade sections) connected to, preferably integrally connected to, a known top radial rotor blade section. In this design, the rotor blade portions cover the outer perimeter and top of an abstract rotor "cage". By arranging the proximal rotor blade portion of such a turbomolecular pump to be at least partially (and preferably fully) fluidly exposed to the volume to be evacuated, the pump speed can be significantly increased, since the pump speed is proportional to both the blade speed and the rotor blade portion length along the axis of rotation. In addition, this makes it possible to extract the gaseous substances also perpendicularly to the rotor axis (drive shaft axis) and in principle along the entire circumference of 360 degrees around the pump rotor stage, which correspondingly increases the effective pumping cross-sectional area. This means that the pump can be reduced in size compared to conventional designs without any loss of pumping power at the same time.
In various embodiments, the rotor blades in the first rotor blade section may be inclined with respect to a first plane perpendicular to the central shaft receiving member, and the rotor blades in the second rotor blade section may be inclined with respect to a generally hollow cylindrical envelope profile generated by the second rotor blade section, which may further include rounded edges (rounded edges) at the points of connection with the rotor blades in the first rotor blade section.
In various embodiments, a third rotor blade section may be foreseen that extends generally radially outward from the central shaft receiving member and is connected to the second rotor blade section at a location between the low pressure input region and the high pressure output region to enhance the mechanical stability of the second rotor blade section, wherein the third rotor blade section deflects gaseous matter generally in the proximal axial direction during operation. Preferably, the rotor blades in the third rotor blade section are inclined with respect to a second plane perpendicular to the central shaft receiving member.
In various embodiments, the number of rotor blades in at least one of the first and second rotor blade sections (which may be the first, second and/or third rotor blade sections, as the case may be) may be odd to reduce resonant vibrations that may occur due to unavoidable mechanical tolerances in the production process.
In various embodiments, adjacent ones of the first and second rotor blade sections (which may be the first, second and/or third rotor blade sections, as the case may be) generally overlap one another to prevent gaseous matter that has entered the interior from escaping or otherwise exiting in directions other than toward the high pressure output region.
In various embodiments, an annular support structure may be foreseen, which is connected with the distal end of the rotor blade in the second rotor blade section to enhance mechanical stability.
In various embodiments, the proximal axial extension (para extension) of the second rotor blade portion may be equal to or greater than the radial extension of the first rotor blade portion. Depending on the amount of proximal axial extension (or height) of the caged rotor, the pump speed can be increased by a factor of three or more compared to a conventional turbomolecular pump of the same diameter having only a proximal pumping action.
In various embodiments, the central shaft receiving member may flare (flare) in at least a partial section from the high pressure output region to the low pressure input region to impart additional momentum in a direction toward the high pressure output region to gaseous matter deflected in a generally radially inward direction from the second rotor blade portion.
In various embodiments, the rotor blades in the second rotor blade section may be helically twisted along the generally hollow cylindrical envelope profile generated by the second rotor blade section to deflect gaseous matter from the second rotor blade section generally in a proximal-to-axial and radially-inward direction.
In various embodiments, at least one conventional rotor-stator stage having radially extending interdigitated rotor-stator vanes may be located downstream of the at least one rotor stage at the low pressure input region. Furthermore, conventional rotor-stator stages may include, for example, Holweck and/or Gator stages, as deemed appropriate by those skilled in the art.
In various embodiments, the rotors in at least one rotor stage may be made of a stable metal such as aluminum, magnesium, titanium, or alloys thereof (e.g., gamma titanium aluminum). Preferably, the rotors in at least one rotor stage are made by additive manufacturing, for example by fusing or casting in one piece using metal powder.
In various embodiments, the fixed frame structure may include a plurality of arcs that converge at a low pressure input region of the central shaft receiving member in the bearing. Preferably, the bearing is one of a magnetic bearing (e.g. having a plurality of permanent magnets) and a ball bearing (e.g. comprising a plurality of ceramic balls having an ultra-smooth surface). It is also preferred that the fixed frame structure further comprises a flange spaced from the low pressure input region along the central axis receiving member, the plurality of arcs being connected to the flange.
In some embodiments, the first rotor blade portion adjacent the low pressure input region may be comprised of a substantially gas impermeable member, such as a substantially solid flat plate or disk, such that the first rotor blade portion exerts little, if any, proximal pumping action. The majority of the pumping action is then effected by the circumferentially radially inward pumping movement of the proximal rotor blade portion. It goes without saying that such a configuration presents the greatest potential when the proximal rotor blade portion is fully exposed to the volume to be evacuated and when the central shaft receiving member is provided with an angled surface, such as a frustoconical diverging surface, and which deflects the gaseous species propelled radially inwardly under the effect of the rotation of the proximal rotor blade portion in the proximal axial direction towards the high pressure output region of the turbomolecular pump.
The invention also relates to a mass spectrometer comprising: receiver having at least one compartment which is maintained at a pressure substantially below ambient atmospheric pressure during operation, for example below 10-5Torr (-1.3X 10)-3Pascal) less than 10-7Torr (-1.3X 10)-5Pascal) or even below 10-11Torr (-1.3X 10)-9Pascal); and a turbomolecular pump according to any of the above embodiments, mounted at the at least one compartment such that the second rotor blade sections substantially protrude into the at least one compartment, thereby extracting gaseous substances from the at least one compartment in a radially inward direction in addition to only in a proximal axial direction as in conventional turbomolecular pumps.
In various embodiments, the at least one compartment may contain at least one mass analyzer or at least one gas source (e.g., a wall degas, collision cell, or gas operated ion source), and the second rotor blade portion may protrude to be directly exposed to gaseous species escaping or otherwise exiting the at least one mass analyzer and emanating from the at least one gas source, respectively. Preferably, at least one compartment contains a time-of-flight drift tube (time-of-flight drift tube), a Kingdon type mass analyser (e.g. from Thermo Fisher Scientific)
) At least one of a 2D or 3D ion trap, a mass filter and an ion cyclotron resonance cell.In various embodiments, coinciding with the multiport configuration, a second rotor stage is foreseen, located at a position spaced from the low pressure input area, having a similar configuration (cage) to at least one rotor stage located at the low pressure input area. It goes without saying that any features and characteristics explained with reference to at least one rotor stage at the low-pressure input region as above apply equally to this second rotor stage, which serves to evacuate the individual compartments to a slightly higher pressure level than the rotor stage at the low-pressure input region. It is particularly preferred that any rotor blade portion extending proximally in the second rotor stage has a smaller proximal axial extension than in the first rotor stage at the low pressure input region (i.e., the second rotor stage may be flatter) in order to mitigate the additional aerodynamic strain created by the higher pressure level at the intermediate pumping port. It goes without saying that in a further development of the technical teaching, a turbomolecular pump may have more than two rotor stages of novel design (in addition to the conventional rotor-stator stages) with respective port openings for fluid connection with other compartments to be evacuated to slightly different pressure levels.
The invention also relates to a mass spectrometer comprising: a receiver having at least two adjacent compartments that are maintained at (different) pressures substantially below ambient atmospheric pressure during operation; and a multi-port configured turbomolecular pump according to any of the embodiments described above, mounted at least two adjacent compartments, such that the second rotor blade section (the second rotor blade section of the first rotor stage located at the low pressure input region) substantially protrudes into a first compartment (maintained at a lowest pressure level) of the at least two adjacent compartments, and the second rotor stage is fluidly connected with a second compartment (maintained at a higher pressure level relative to the first compartment) of the at least two adjacent compartments.
Drawings
The invention may be better understood by reference to the following drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention (generally, schematically):
fig. 1 schematically depicts a principle based on the present invention.
FIG. 2 presents several views of a first novel rotor design in accordance with the principles of the present invention.
FIG. 3 presents several views of another new rotor design in which the first radial rotor blade portion at the low pressure input end smoothly transitions to the proximal rotor blade portion.
FIG. 4A shows several views of yet another novel rotor design in which the rotor blades in the near-axis rotor blade section are helically deformed along a circumferential profile.
For clarity, fig. 4B complements the illustration in fig. 4A with less detail.
Fig. 5A shows a turbomolecular pump including a novel rotor design and its exemplary implementation in a receiver of a mass spectrometer.
Fig. 5B illustrates another exemplary embodiment of a turbomolecular pump featuring a novel rotor design in the drift tube of a time-of-flight mass analyzer.
Fig. 6A depicts a multi-port turbomolecular pump that includes a novel rotor design in several different views.
Fig. 6B depicts an exemplary embodiment of a multiport turbomolecular pump as shown in fig. 6A in a receiver of a mass spectrometer.
Detailed Description
While the invention has been shown and described with reference to a number of different embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.
The basic idea of the invention is to increase the pump speed by increasing the rotor blade cross section exposed to the chamber to be evacuated. This increases the likelihood that molecules will impact the rotor blade under high to ultra-high vacuum. With reference to the concept schematically illustrated in fig. 1, this object may be achieved by providing a rotor blade assembly of cage-like construction, which is preferably completely exposed to the vacuum chamber. The caged rotor blade assembly includes rotor blade portions arranged proximally along a circumference of an imaginary "cage". Additionally, the caged rotor blade assembly may include one or more sets of radial rotor blade portions to hold the proximal rotor blade portions in place.
The pump speed is increased by the length of the part of the near-axis rotor blade moving at the peripheral speed compared to the tip only (active) of the radially extending rotor blade in conventional turbomolecular pumps known in the prior art. This exposed arrangement also allows molecules to impact and be drawn into the caged rotor assembly radially inward from all sides and proximally, see the lower view in fig. 1. This is particularly important at pressures with mean free path greater than 10 cm. By virtue of the vacuum pressure achieved at the low pressure input region and the near axial extension of the near axial rotor blade portion, the pump speed can be significantly increased compared to a conventional turbomolecular pump of the same diameter.
Fig. 2 shows a first example of a novel cage rotor design in several views. Left side of the first row: a bottom plan view supplemented by a side cross-sectional view on the right and an isometric cross-sectional view further to the right; left side of second row: a plan side view supplemented by a cutaway plan top view on the right and an isometric view further to the right; third row left: a plan top view.
In the illustrated embodiment, the rotor 200 has a central
The rotor blades in the first
Third
Adjacent ones of the first, second and third
An
The central
Fig. 3 shows another example of the novel cage rotor design in several views. Left side of the first row: a bottom plan view supplemented by a side cross-sectional view on the right and an isometric cross-sectional view further to the right; left side of second row: a plan side view supplemented by a cutaway plan top view on the right and an isometric view further to the right; third row left: a plan top view.
In the illustrated embodiment, the
The rotor blades in the first
Third
Adjacent ones of the first, second, and third
An
The central
In the illustrated embodiment, the number of rotor blades in the first, second, and third
Compared to the embodiment of fig. 2, the
Fig. 4A (and fig. 4B) depict yet another example of a novel cage rotor design in several views. Left side of the first row: a bottom plan view supplemented by a side cross-sectional view on the right and an isometric cross-sectional view further to the right; left side of second row: a plan side view supplemented by a cutaway plan top view and an isometric view of the right side; third row left: a plan top view.
In the illustrated embodiment, the rotor 400 has a central
The rotor blades in the first
In the illustrated example, the rotor blades in the second
The third
Adjacent rotor blades in the first, second, and third
The
In the illustrated embodiment, the proximal axial extension X of the second
The central
In the illustrated embodiment, the number of rotor blades in the first, second and third
Fig. 4B shows the embodiment of fig. 4A with less detail. For clarity, all but two of the first, second, and third
The previous fig. 1-4 describe an embodiment of a mechanically stabilized cage rotor. Stress simulations by computer program showed that: the maximum displacement of the rotor blades in the near-axis rotor blade section at 60000RPM is less than 0.1 mm and does not crack the blades, which means higher mechanical integrity. The model is based on the following cage-like structure: the cage has a diameter of 60mm (2 x R) built around two radial rotor blade sections, wherein the tips of the proximal rotor blades are connected to each other by an annular support. The axial height X is set to 42 mm. Assuming the material is 6075 aluminum (T-6 aircraft aluminum), the total weight of the exemplary rotor is approximately 60 grams.
Fig. 5A shows, by way of example, a novel rotor design concept in a
As is apparent from the upper drawing in fig. 5A, the
As is apparent from the lower drawing in fig. 5A, only one
Conventional turbomolecular pumps are mounted on such compartments that are substantially flush with the first rotor stage at the low pressure input, which largely sinks into the floor or side walls of the receiver (see the schematic of the upper diagram of fig. 1), and are to be evacuated, but the novel rotor and turbomolecular pump design of the present invention deviates from this conventional approach in the following respects: the
Furthermore, in the embodiment shown in the lower diagram of fig. 5A, the
Fig. 5B depicts how a turbomolecular pump with the features of a novel rotor design (e.g., taken from any of the embodiments shown in fig. 2, 3, and 4A), such as the turbomolecular pump shown in the upper diagram of fig. 5A, can be used to evacuate a drift tube of a time-of-flight mass analyzer (OTOF) with orthogonal acceleration in this example. The general concept of OTOF mass spectrometers is well known to those skilled in the art and need not be discussed further herein.
In the illustrated embodiment, ions to be analyzed are supplied to the time-of-flight analyzer from an ion source (not shown) that is fluidly attached and the ions are optically attached to the lower leg ("horizontal leg") 534 of the L-shaped receiver. A
Three
Each of the
The embodiment shown in fig. 5B enables the construction of a
Fig. 6A shows a multi-port cage rotor design in several different views. Left panel: a cross-sectional side view; the middle part: a plan side view; right panel: an isometric view.
The embodiment of the
Further, the
The turbomolecular pump of fig. 6A has a fixed frame structure comprising a plurality of arcs 620, the plurality of arcs 620 converging at an end of the first central shaft receiving member 602A near the low pressure input region 604A in a bearing 622, which bearing 622 may be a magnetic bearing with a plurality of permanent magnets or a ball bearing comprising a plurality of ceramic balls with ultra-smooth surfaces. The ball bearing can be lubricated by special lubricating grease with extremely low vapor pressure. In addition, the fixed frame structure includes a flange or step 624 spaced apart from the low pressure input region 604A, and the plurality of arcs 620 are connected to the flange or step 624. Specifically, the flange or step 624 serves to mount the
The second central shaft receiving member 602B of the
The second central shaft receiving member 602B may flare in a section-wise direction from the high pressure output region 604B to the low pressure input region 604A to impart additional momentum in a direction toward the high pressure output region to gaseous species deflected generally radially inward from the proximal rotor blade portions in the second
A conventional rotor-stator stage 628 with radially extending interdigitated rotor-stator blades is located between a
Fig. 6B illustrates, by way of example, the use of a multiport
The mass spectrometer has a receiver comprising at least two adjacent compartments, of which two
Fig. 6B shows an example of a multi-port turbo-
The rotor stage(s) in the embodiments of any of the foregoing fig. 1-6 may be made of a stable metal, such as aluminum, magnesium, titanium, or alloys thereof. In particular, the rotor stage(s) may be fabricated by additive manufacturing (e.g., powder fusion) or integral casting, for example, using a stable material such as titanium aluminide (TiAl).
Aluminum and titanium are the preferred metals for additive manufacturing of metal parts and have extremely high mechanical strength and temperature resistance. Additive manufacturing has the additional advantage that very unusual alloys with properties different from the standard alloy can be used.
As an example of a low weight, high mechanical strength material, γ TiAl, an intermetallic compound of aluminum and titanium (titanium aluminide), has excellent mechanical properties as well as oxidation and corrosion resistance at high temperatures (over 600 degrees celsius). γ TiAl is used in blades of modern aircraft turbine engines because γ TiAl has an excellent thrust-to-weight ratio. Additive manufacturing can produce parts composed of such alloy intermetallic compounds.
The present invention has been shown and described above with reference to a number of different embodiments thereof. However, it will be apparent to one skilled in the art that various aspects or details of the invention may be changed or combined in any combination without departing from the scope of the invention. In general, the foregoing description is for the purpose of illustration only and is not intended to be limiting, the invention being defined only by the appended claims and including any equivalents as appropriate.
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