ZA200405764B - Stabilized grain size refractory metal power metallurgy mill products. - Google Patents
Stabilized grain size refractory metal power metallurgy mill products. Download PDFInfo
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- ZA200405764B ZA200405764B ZA200405764A ZA200405764A ZA200405764B ZA 200405764 B ZA200405764 B ZA 200405764B ZA 200405764 A ZA200405764 A ZA 200405764A ZA 200405764 A ZA200405764 A ZA 200405764A ZA 200405764 B ZA200405764 B ZA 200405764B
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- Prior art keywords
- powder
- niobium
- mill product
- ppm
- oxygen
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- 239000003870 refractory metal Substances 0.000 title claims description 23
- 238000005272 metallurgy Methods 0.000 title description 2
- 239000000843 powder Substances 0.000 claims description 85
- 238000000034 method Methods 0.000 claims description 56
- 230000008569 process Effects 0.000 claims description 48
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 44
- 239000001301 oxygen Substances 0.000 claims description 44
- 229910052760 oxygen Inorganic materials 0.000 claims description 44
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 41
- 230000000930 thermomechanical effect Effects 0.000 claims description 31
- 239000010955 niobium Substances 0.000 claims description 27
- 229910052758 niobium Inorganic materials 0.000 claims description 26
- 238000012545 processing Methods 0.000 claims description 25
- 229910052751 metal Inorganic materials 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 20
- 238000001513 hot isostatic pressing Methods 0.000 claims description 16
- 238000001125 extrusion Methods 0.000 claims description 12
- BFRGSJVXBIWTCF-UHFFFAOYSA-N niobium monoxide Chemical compound [Nb]=O BFRGSJVXBIWTCF-UHFFFAOYSA-N 0.000 claims description 12
- 238000007254 oxidation reaction Methods 0.000 claims description 11
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 11
- 239000003966 growth inhibitor Substances 0.000 claims description 10
- 239000003112 inhibitor Substances 0.000 claims description 10
- 229910052715 tantalum Inorganic materials 0.000 claims description 10
- 239000000956 alloy Substances 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 8
- 239000011888 foil Substances 0.000 claims description 8
- 229910052749 magnesium Inorganic materials 0.000 claims description 8
- 239000011777 magnesium Substances 0.000 claims description 8
- -1 zirconium metals Chemical class 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 6
- 150000002739 metals Chemical class 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 229910001257 Nb alloy Inorganic materials 0.000 claims description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical group [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 3
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 239000011733 molybdenum Substances 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 229910052702 rhenium Inorganic materials 0.000 claims description 3
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 claims description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 239000010937 tungsten Substances 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- 229910052814 silicon oxide Inorganic materials 0.000 claims 1
- 238000005303 weighing Methods 0.000 claims 1
- 238000009694 cold isostatic pressing Methods 0.000 description 18
- 238000005245 sintering Methods 0.000 description 15
- 239000000463 material Substances 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 238000007596 consolidation process Methods 0.000 description 6
- 238000004663 powder metallurgy Methods 0.000 description 6
- 238000003825 pressing Methods 0.000 description 6
- 238000005242 forging Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 235000012438 extruded product Nutrition 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 238000001192 hot extrusion Methods 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- 229910052987 metal hydride Inorganic materials 0.000 description 2
- 150000004681 metal hydrides Chemical class 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000000754 repressing effect Effects 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 206010037660 Pyrexia Diseases 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000002730 additional effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000009924 canning Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 150000004678 hydrides Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000009707 resistance sintering Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1003—Use of special medium during sintering, e.g. sintering aid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/145—Chemical treatment, e.g. passivation or decarburisation
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
- C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
- C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
- C22C32/0031—Matrix based on refractory metals, W, Mo, Nb, Hf, Ta, Zr, Ti, V or alloys thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F2003/1032—Sintering only comprising a grain growth inhibitor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
- B22F2005/002—Tools other than cutting tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
Description
STABILIZED GRAIN SIZE REFRACTORY
METAL POWDER METALLURGY MILL PRODUCTS
The invention relates generally to metal mill products (and fabricated parts) made from powders of refractory metals including the elemental metals and their alloys and, more particularly to the use of oxide dopants for grain size stabilization in mill products and fabricated parts to be subjected to high temperature application usage and/or high tempera- ture fabrication processes.
Users of refractory metals have had a long-standing interest in replacing tantalum with niobium. One driving force for such replacement of tantalum is price as well as the limited availability of tantalum. Many mill products involve high temperature exposure in fabrication and/or use. The high temperatures can cause grain growth. In various applications large grains, as a consequence of such grain growth, are detrimental to the performance of the material. This has been a limitation of niobium substitution for tantalum. Other limitations include lesser strength and hardness as-fabricated niobium and its alloys.
Currently, areas of interest include furnace parts, sintering trays and deep drawn cups as used for manufacturing synthetic diamonds.
These products require material with small grain size. Furnace parts particularly require the material to have slow grain growth during service in order to prevent premature deterioration of the mechanical properties.
Currently tantalum material with stabilized grain size, due to alloying additions or other artifacts, is used for wire or sheet. In one embodiment or state of interaction, SiO; is used as a grain stabilizer. The disadvantage of such a manufacturing method (resistance-sintering) for grain size stabilized tantalum powder metallurgy (P/M) material is that it is limited to a lot size of 30 pounds for tantalum and approximately 15 pounds for niobium. lt is desirable to make lot sizes of up to 1000 pounds of tantalum and 500 pounds of niobium respectively.
Current manufacturing methods for large P/M sheet sizes/strip length are not capable of providing large pieces of sheet or long coils of sheet with the same low level of oxygen content and good mechanical properties
It is an object of this invention to provide a powder metallurgy (P/M) route to fabrication of refractory metals in large lots with low oxygen content and to provide resultant mill products with low oxygen content.
It is a further object of this invention to provide a P/M source for mill products and eventual mill products with a finer grain and a decreased grain growth than are achieved with ingot source materials.
These objects are applicable to refractory metals generally and more particularly to niobium and its alloys.
The objects set forth above as well as further and other objects and advantages of the present invention are achieved by the invention as described hereinbelow
The invention relates to a process for making a metal mill product from a refractory metal powder comprising (a) providing a low oxygen refractory metal powder; (b) adding to the powder a grain growth inhibitor to the low oxygen refractory metal powder before consolidating the powder, (c) consolidating the powder by either hot isostatic pressing, extrusion or another thermomechanical working process; and (d) subjecting the consolidated powder to subsequent thermomechanical processing, and thereby forming the mill product. The invention also relates to products made from such a process.
Grain growth inhibitors are added to niobium powder by blending inhibitors such as SiO, and Y,Os3 prior to consolidation or as a residue of a de-oxidation process where magnesium is added to capture the oxygen from the niobium powder and form magnesium oxide during the de- oxidation process.
The powder is consolidated either by hot isostatic pressing (HIPing), extrusion or other thermomechanical working. Such methods of consolidation are capable of providing suitable P/M sheet bars with a weight of up to several hundred pounds, e.g., five hundred pounds, one thousand pounds or more. Subsequent thermomechanical processing of the P/M sheet bar is applied similarly to then P/M derived refractory metals as to metals from ingot sources.
The present invention inhibits grain growth in niobium P/M sheets during high temperature exposure. A low oxygen niobium powder (< about 400 ppm, preferably < about 200 ppm) is needed as a starting material. Powders with a higher content in oxygen cannot be consolidated to full density and/or will not yield good mechanical properties. | :
Fig. 1 is a flow chart showing a process of the present invention to create stabilized grain size powder; and
Figs. 2-4 are flow charts showing examples of consolidating steps to create products made of stabilized grain size powder.
The invention relates to a process for making a metal mill product from a refractory metal powder comprising (a) providing a low oxygen refractory metal powder; (b) adding to the powder a grain growth inhibitor to the low oxygen refractory metal powder before consolidating the powder, (c) consolidating the powder by either hot isostatic pressing, extrusion or another thermomechanical working process; and : (d) subjecting the consolidated powder to subsequent thermomechanical processing, and thereby forming the mill product. The invention also relates to products made from such a process.
The low oxygen niobium powder can be any powder, which when used in accordance to the invention, enables user to meet an object of the invention. The metal powders with stabilized grain size of the present invention are preferably produced via the following procedure as discussed in U.S. Patent 6,261,337, incorporated herein in its entirety.
Niobium alloys can also be used. in other embodiments, instead of using niobium powders, powders made from a refractory metal selected from hafnium, molybdenum, niobium, rhenium, tantalum, tungsten, vanadium, and zirconium metals can be used. Also, alloys of these metals can also be used.
As illustrated in Fig. 1, low oxygen niobium and grain growth inhibitor powders (for example SiO; or Y,03) are blended to form low oxygen powder with grain size inhibitors. Figs. 2-4 illustrate the consolidation steps with the master blend. The physical processes of blending and consolidating achieve a uniform distribution of grain growth inhibiting particles in the powder metal sheet bars. The powders are made by the process described in US 6,261,337 and as described herein.
These powders are blended to produce the desired alloy compo- sition. The powders are then sealed in an evacuated can, heated to a desired temperature, and extruded such that the extrusion ratio is at least 8:1. This is done to completely consolidate the niobium powders and the included inhibitors. The can may be removed either just before or just after the rolling operation.
The above process can afford advantages of more stable grain size in the final material, more uniform material properties (such as ultimate tensile strength and hardness), lower manufacturing costs, better control of fiber size, and greater flexibility for alloy modifications and control of properties.
Niobium sheets produced from powder blends of niobium and grain inhibitors, for example silicon, were tested for grain growth, ultimate tensile strength, and hardness. The test results are presented in Table 1 below.
Table 1 1150°C Ultimate 1065°C @180 1300°C Tensile
Silicon | @90 min min @180 min | Strength Hardness ppm ASTM ASTM ASTM KSI VICKERS 0 | 95 | 95 | 75 | 493 | 114
I A RE RE EE RE
150 | 95 | 90 | 80 [ 503 | 117
IE I EE RE RE
I EE I EE
Nb UM
P/M sheet with grain growth inhibitors, preferably silicon, of 0, 150, and 300 ppm were thermomechanical processed to a thickness of 0.015 inches and annealed at 1065°C for 90 minutes to produce grain sizes of approximately ASTM 9.5. Niobium sheet produced from ingot metallurgy (I/M) a grain size of approximately ASTM 5.5 under the same anneal heat treat conditions. The P/M and I/M test samples were subjected to addi- tional annealing heat treatments at 1150°C for 180 minutes and 1300 °C for 180 minutes. The P/M test samples yielded grain sizes greater than
ASTM 7.0 compared to I/M test samples that yielded grain sizes coarser than ASTM 1.
Additionally, the higher P/M Ultimate Tensile Strength of 49.3 KSI, 50.3 KSI, and 49.5 KSI and hardness of 114 VHN, 117 VHN, and 125
VHN are significant improvements over typical I/M material of Ultimate
Tensile Strength of 32 KSI and hardness of 72 VHN. The fine grain sizes and improved tensile strength and hardness after heat treatment of the
P/M material is a significant advantage, compared to I/M material, in applications where large amounts of deformation are required during fabrication, such as deep drawn diamond cups, or capacitor cans.
Alternatively, the blended powders may be isostatically pressed into a bar prior to canning and extrusion, as illustrated in Fig. 2. The advan-
tage of this method would be to put a higher weight into the compact prior to extrusion to aid in consolidation and increase yield per extrusion.
Now returning to Fig. 1, niobium hydride powder is placed into a vacuum chamber, which also contains a metal having a higher affinity for oxygen, such as calcium or magnesium, preferably the latter. Preferably, the starting hydride powder has oxygen content less than about 1000 ppm. The chamber is heated to the dehydration temperature to remove the hydrogen, then heated to the deoxidation temperature to produce a powder of niobium or alloy of niobium having a target reduced oxygen content of less than about 400 ppm preferably below 200 ppm and more preferably below 100 ppm. The magnesium, containing the oxygen, is then removed from the metal powder by evaporation and subsequently by selective chemical leaching or dissolution of the powder.
For example, a niobium powder with less than 400 ppm oxygen can be produced by the deoxidization of niobium hydride under partial pressure of argon. Niobium hydride powder would be blended with 0.3 © wt.-% magnesium and placed in a vacuum furnace retort, which is evacuated, and backfilled with argon. The pressure in the furnace would be set at about 100 microns with Argon flowing and the vacuum pump running.
The furnace temperature would be ramped to about 650°C in approximately 50°C increments, held until temperature equalized, then ramped up to 950°C in approximately 50°C increments. When the temperature equalized at 950°C it would be held for about two hours. After such hold, the furnace is shut down. Once the furnace cools its powder content is removed from the retort.
The magnesium, containing the oxygen, would then be removed from the metal powder by acid leaching to produce the resulting niobium powder having an oxygen content of less than 300 ppm.
As described above, in the process for producing formed powder metal products of niobium, the metal hydride powder is deoxidized to an oxygen content of less than about 400 ppm. The powder is consolidated to form a niobium or alloy product, having an oxygen content below about about 400 ppm, or below about 300 ppm or below about 200 ppm or below about 100 ppm, but for many powder metallurgy purposes between about 100 ppm and 150 ppm. According to the present invention, a formed refractory metal product (niobium product), having a stabilized grain size, may be produced from metal hydride powder, as treated as described above, by any known powder metallurgy techniques.
Exemplary of these powder metallurgy techniques used for forming the products are the following, in which the steps are listed in order of performance. Any of the following single techniques or sequences of techniques may be utilized in the present invention: cold isostatic pressing, sintering, encapsulating, hot isostatic pressing and thermomechanical processing; cold isostatic pressing, sintering, hot isostatic pressing thermomechanical processing; cold isostatic pressing, encapsulating, hot isostatic pressing and thermomechanical processing; cold isostatic pressing, encapsulating and hot isostatic pressing; encapsulating and hot isostatic pressing; cold isostatic pressing, sintering, encapsulating, extruding and thermomechanical processing; cold isostatic pressing, sintering, extruding, and thermomechanical processing; cold isostatic pressing, sintering, and extruding; cold isostatic pressing, encapsulating, extruding and thermomechanical processing; cold isostatic pressing, encapsulating and extruding; encapsulating and extruding; mechanical pressing, sintering and extruding; cold isostatic pressing, sintering, encapsulating, forging and thermomechanical processing; cold isostatic pressing, encapsulating, forging and thermomechanical processing; cold isostatic pressing, encapsulating and forging; cold isostatic pressing, sintering, and forging; cold isostatic pressing, sintering and rolling; encapsulating and forging; encapsulating and rolling. cold isostatic pressing, sintering and thermomechanical processing; mechanical pressing and sintering; and mechanical pressing, sintering, repressing and resintering; other combinations of consolidating, heating and deforming may also be utilized.
The production of a formed niobium product having a stabilized grain size can be achieved by cold isostatic pressing of various kinds of known niobium powders to form a compact, followed by a hot isostatic pressing (HIPing) step to densify the compact and then thermomechanical processing of the powder compact for further densification and completion of the bonding, as illustrated in Fig. 3. Preferably, niobium powder with grain size inhibitors would be cold isostatically pressed at 60,000 pounds/sq. in. and room temperature, into a compact with rectangular or, preferably, round cross section, then hermetically encapsulated and hot isostatically pressed (HPed) at 40,000 Ibs.1sq. in. and 1300°C for four hours. The HIPed compact would be unencapsulated and converted to sheet or foil by thermomechanical processing steps.
A similar process, as illustrated in Fig. 4, of just cold isostatic pressing, sintering and thermomechanical processing using niobium powder having an oxygen content of less than 300 ppm can be conducted by cold isostatically pressing at 60,000 Ibs./sq. in. into a bar shape preform. This preform would be sintered at 1500°C for two hours in a vacuum of less than about 0.001 Torr to yield a preform having a density of about 95% theoretical density (Th) and less than 400 ppm oxygen. The sintered preform would be converted into sheet and foil by thermomecha- nical processing steps.
Production of a formed niobium sheet or foil having a stable grain size by hot extrusion and thermomechanical processing can be made, using niobium powder having an oxygen content of less than 400 ppm as the starting powder. This powder can be hermetically encapsulated then extruded through a rectangular or, preferably, round die at 1000°C to produce an extruded product having oxygen content of less than 400 ppm.
The extruded product can be converted to sheet or foil by the thermo- mechanical processing.
Niobium sheet or foil with oxygen content of less than 400 ppm can be produced by cold isostatic pressing, hot extrusion and thermomecha- nical processing. This compact made by cold isostatically pressing could be hermetically encapsulated then extruded at 1000°C to produce an extruded product with an oxygen content of about 300 ppm which can be converted into sheet and foil by thermomechanical processing steps.
Niobium products having stable grain size can be prepared by mechanical pressing, sintering, repressing and resintering.
Niobium powder blend having oxygen content of less than 400 ppm can be utilized as the starting powder. lt is placed in a die and mecha- nically pressed, using uniaxial pressure. The pressed tablet should be then sintered at 1500°C for two hours in a vacuum evacuated to less than about 0.001 Torr. The sintered tablet would then be repressed and resintered at 1500°C for two hours in a vacuum evacuated to less than about 0.001 Torr.
The resintered tablet will have oxygen content of less than about 400 ppm and be suitable for thermomechanical processing to produce a formed niobium product.
In one embodiment, a copper or steel container is filled with niobium powder, evacuated, hermetically sealed, and extruded through a die to give a 10:1 extrusion ratio. The copper container is removed by acid treatment and the extruded bar is thermo-mechanically processed into a - sheet form flat. In another embodiment, a steel container is filled with the niobium powder, evacuated, hermetically sealed and HiPed. The steel container is removed by machining and the HIPed piece is thermo mechanically processed into a sheet form flat.
Anneals may be used to improve workability of the material in between two deformation steps or to adjust grain size and texture through recrystallization although a final anneal may not be necessary. When the powder is canned during the consolidation (usually to protect it from the environment at high temperature), the can will bond to the niobium.
In another embodiment, the process provides P/M sheets of large size (>100 pounds) having good mechanical properties and small stable grain size, capable of a higher yield than conventional P/M processes for sheet manufacture, typically 50 pounds or less. Low oxygen niobium powder of less than 400 ppm, preferably less than 150 ppm, of non-spherical particles and sizing less than 250 microns FAPD (Fisher
Average Particle Diameter), is provided per processes described herein.
Powders with a higher content in oxygen cannot be consolidated to full density and/or will not yield good mechanical properties. The powder is consolidated to full density either by HIPing (hot isostatic pressing) or by extrusion. Both methods of consolidation are capable of providing suitable
P/M sheet bars with a weight of up to several hundred pounds.
Thermomechancial processing of the P/M sheet bar is similar to standard processes.
Numerous variations and modifications may obviously be made without departing from the present invention. Accordingly, it should be clearly understood that the forms of the present invention herein described are illustrative only and are not intended to limit the scope of the invention.
Claims (1)
- WHAT IS CLAIMED IS:1. A process for making a metal mill product from a refractory metal powder comprising: (a) providing a low oxygen refractory metal powder; (b) adding to the powder a grain growth inhibitor to the low oxygen refractory metal powder before consolidating the powder, (¢) consolidating the powder by either hot isostatic pressing; extrusion or another thermomechanical working process; and (d) subjecting the consolidated powder to subsequent thermomechanical processing, and thereby forming the mill product.2. The process of Claim 1, wherein the refractory metal is niobium or a niobium alloy.3. The process of Claim 1, wherein the refractory metal is selected from the group consisting of hafnium, molybdenum, rhenium, tantalum, tungsten, vanadium, and zirconium metals, alloys of the foregoing metals, and combinations thereof.4. The process of Claim 1, wherein prior to consolidating the powder, the grain growth inhibitor is added to the powder by (i) blending an inhibitor component with the powder or (ii) a residue of a de-oxidation process.5. The process of Claim 4, wherein the residue is a residue formed in a de-oxidation process, wherein magnesium is added to capture the oxygen from the niobium powder and magnesium oxide forms during the de-oxidation process.6. The process of Claim 4, wherein the inhibitor component is selected from the group consisting of SiOz, Y203, and mixtures thereof.7. The process of Claim 1, wherein the low oxygen niobium powder has an oxygen content that is less than about 400 ppm.8. The process of Claim 1, wherein the low oxygen niobium powder has an oxygen content that is less than about 300 ppm.9. The process of Claim 1, wherein the low oxygen niobium : powder has an oxygen content that is less than about 200 ppm.10. The process of Claim 1, wherein the low oxygen niobium powder has an oxygen content ranging from about 100 ppm to about 150 ppm.11. The process of Claim 1, wherein the low oxygen niobium powder has an oxygen content that is less than about 100 ppm.12. The process of Claim 1, wherein the mill product is a sheet . containing oxide particles.13. The process of Claim 1, wherein the mill product is a foil.14. The process of Claim 1, wherein the mill product is a sheet weighing at least 100 pounds.16. A mill product comprising a stabilized grain size made from a process comprising: (a) providing a low oxygen refractory metal powder; (b) adding to the powder, before consolidating the powder, a grain growth inhibitor to the low oxygen refractory metal powder, (c) consolidating the powder by either hot isostatic pressing, extrusion or another thermomechanical working process; and (d) subjecting the consolidated powder to subsequent thermomechanical processing, and thereby forming the mill product.16. The process of Claim 15, wherein the refractory metal is niobium or a niobium alloy.17. The mill product of Claim 15, wherein the refractory metal is selected from the group consisting of hafnium, molybdenum, rhenium, tantalum, tungsten, vanadium, and zirconium metals, alloys of the foregoing metals, and combinations thereof.18. The mill product of Claim 15, wherein prior to consolidating the powder, the grain growth inhibitor is added to the powder by blending an inhibitor component or (ii) a residue of a de-oxidation process.19. The mill product of Claim 15, wherein the residue is a residue formed in a de-oxidation process, wherein magnesium is added to capture the oxygen from the niobium powder and magnesium oxide forms during the de-oxidation process.20. The mill product of Claim 18, wherein the inhibitor component is selected from the group consisting of SiO, Y203 and mixtures thereof.21. The mill product of Claim 15, wherein the low oxygen ~ § niobium powder has an oxygen content that is less than about 400 ppm.22. The mill product of Claim 15, wherein the low oxygen niobium powder has an oxygen content that is less than about 300 ppm.23. The mill product of Claim 15, wherein the mill product is a sheet or a foil.24. A process for making a metal mill product from a niobium powder comprising: (a) providing a low oxygen niobium powder having an oxygen content that is less than about 400 ppm; (b) adding to the powder a grain growth inhibitor to the low oxygen niobium powder before consolidating the powder by blending an inhibitor component or (ii) a residue of a de-oxidation process, wherein the residue is a residue formed in a de-oxidation process, wherein magnesium is added to capture the oxygen from the niobium powder and magnesium oxide forms during the de-oxidation process, (c) consolidating the powder by either hot isostatic pressing, extrusion or another thermomechanical working process; and (d) subjecting the consolidated powder to subsequent thermomechanical processing, and thereby forming the mill product.
Applications Claiming Priority (1)
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US35114602P | 2002-01-23 | 2002-01-23 |
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ZA200405764A ZA200405764B (en) | 2002-01-23 | 2004-07-20 | Stabilized grain size refractory metal power metallurgy mill products. |
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US (1) | US20050118052A1 (en) |
EP (1) | EP1506322A2 (en) |
JP (1) | JP2005516116A (en) |
KR (1) | KR20040091627A (en) |
CN (1) | CN1623005A (en) |
BR (1) | BR0307073A (en) |
CA (1) | CA2473493A1 (en) |
IL (1) | IL162904A0 (en) |
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WO (1) | WO2003062482A2 (en) |
ZA (1) | ZA200405764B (en) |
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US20060115372A1 (en) * | 2003-01-31 | 2006-06-01 | Prabhat Kumar | Refractory metal annealing bands |
KR20100085024A (en) * | 2007-10-15 | 2010-07-28 | 하이-템프 스페설티 메탈스, 인코포레이티드 | Method for the production of tantalum powder using reclaimed scrap as source material |
KR101364607B1 (en) * | 2013-09-11 | 2014-02-20 | 한국지질자원연구원 | Method for refining grain of sintered body by reducing oxygen content from metallic molybdenum powder |
US9238852B2 (en) * | 2013-09-13 | 2016-01-19 | Ametek, Inc. | Process for making molybdenum or molybdenum-containing strip |
CN106567048B (en) * | 2016-11-10 | 2018-11-27 | 洛阳科威钨钼有限公司 | A kind of manufacturing method of large size High-Purity Molybdenum alloy rotary target material |
US11274363B2 (en) * | 2019-04-22 | 2022-03-15 | Nxp Usa, Inc. | Method of forming a sputtering target |
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AT386612B (en) * | 1987-01-28 | 1988-09-26 | Plansee Metallwerk | CRISP-RESISTANT ALLOY FROM MELTING-MELTING METAL AND METHOD FOR THEIR PRODUCTION |
US6261337B1 (en) * | 1999-08-19 | 2001-07-17 | Prabhat Kumar | Low oxygen refractory metal powder for powder metallurgy |
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2003
- 2003-01-21 RU RU2004125856/02A patent/RU2004125856A/en not_active Application Discontinuation
- 2003-01-21 MX MXPA04007104A patent/MXPA04007104A/en not_active Application Discontinuation
- 2003-01-21 CA CA002473493A patent/CA2473493A1/en not_active Abandoned
- 2003-01-21 JP JP2003562348A patent/JP2005516116A/en not_active Withdrawn
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- 2003-01-21 KR KR10-2004-7011314A patent/KR20040091627A/en not_active Application Discontinuation
- 2003-01-21 EP EP03705856A patent/EP1506322A2/en not_active Withdrawn
- 2003-01-21 NZ NZ534212A patent/NZ534212A/en unknown
- 2003-01-21 PL PL03371625A patent/PL371625A1/en not_active Application Discontinuation
- 2003-01-21 BR BR0307073-5A patent/BR0307073A/en not_active IP Right Cessation
- 2003-01-21 CN CNA038026465A patent/CN1623005A/en active Pending
- 2003-01-21 RS YU64904A patent/RS64904A/en unknown
- 2003-01-21 WO PCT/US2003/001823 patent/WO2003062482A2/en not_active Application Discontinuation
- 2003-01-22 TW TW092101288A patent/TWI262109B/en not_active IP Right Cessation
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WO2003062482A2 (en) | 2003-07-31 |
CN1623005A (en) | 2005-06-01 |
US20050118052A1 (en) | 2005-06-02 |
KR20040091627A (en) | 2004-10-28 |
BR0307073A (en) | 2004-12-28 |
PL371625A1 (en) | 2005-06-27 |
TWI262109B (en) | 2006-09-21 |
JP2005516116A (en) | 2005-06-02 |
MXPA04007104A (en) | 2004-10-29 |
NZ534212A (en) | 2006-04-28 |
CA2473493A1 (en) | 2003-07-31 |
WO2003062482A3 (en) | 2004-02-26 |
EP1506322A2 (en) | 2005-02-16 |
IL162904A0 (en) | 2005-11-20 |
TW200307583A (en) | 2003-12-16 |
RU2004125856A (en) | 2005-06-10 |
RS64904A (en) | 2006-10-27 |
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