CA1178459A - Thermomechanical processing of dispersion- strengthened precious metal alloys - Google Patents
Thermomechanical processing of dispersion- strengthened precious metal alloysInfo
- Publication number
- CA1178459A CA1178459A CA000360277A CA360277A CA1178459A CA 1178459 A CA1178459 A CA 1178459A CA 000360277 A CA000360277 A CA 000360277A CA 360277 A CA360277 A CA 360277A CA 1178459 A CA1178459 A CA 1178459A
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- Canada
- Prior art keywords
- process according
- dispersion
- carried out
- precious metal
- yttria
- Prior art date
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-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/14—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of noble metals or alloys based thereon
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- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Powder Metallurgy (AREA)
- Reinforced Plastic Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for producing sheets of dispersion-strengthened precious metal alloys having superior creep resistance is disclosed. According to this invention dispersion-strengthened precious metal alloys are thermomechanically processed to help develop a creep resistance microstructure.
A process for producing sheets of dispersion-strengthened precious metal alloys having superior creep resistance is disclosed. According to this invention dispersion-strengthened precious metal alloys are thermomechanically processed to help develop a creep resistance microstructure.
Description
'3 This invention relates to thermomechanical processlng of dispersion-strengthened precious metal alloys The present invention can provide alloys containing platlnum, palladlum, rhodium and gold which are useful tn the production of glass fibers.
One of the most exacting applications of platinum is in the production of glass fibers. Molten glass often at temperatures ranging from 1200 to 1600C passes through a series of orifices in a bushing. Advances in glass fiber production are demanding both larger bushings and higher operating temperatures.
Structural components such as these at elevated tem-peratures under constant loads experience continuous dimension-al changes or creep during their lives. This creep behavior depends upon the interaction between the external conditions ~load, temperaturej and the microstructure of the component.
In recent times, increased resistance to creep of material systems has been accomplished by using a dispersion of very small, hard particles (called dispersoids) to strengthen the microstructure of the component. These systems have become to be known as dispersion-stre~gthened metals and alloys and the dispersoids used are usually oxides. A recent development in dispersion-strengthening is mechanical alloying which uses a high energy ball mill to achieve the intimate mechanical ; mixing typical of the process. An attritor mill or vibratory mill also can be used.
Accordingly, the present invention provides a process for producing sheets of a dispersion-strengthened precious - metal alloy which includes (1) platinum or a platinum alloy and (2) at least one metal oxide, comprising the step of .~
,, .
thermomechanically processing the compacted disperslon-strengthened precious metal alloy.
Preferably a series of mechanical deformation and annealing cycles are used to help develop a creep resistant microstructure. Specifically, this may be achieved by rolllng and annealing a powder compact of dispersion-strengthened pre-cious metal. The material may be cross-rolled as well as longitudinally rolled or just longitudinally rolled.
Figure 1 is a schematic drawing of the rolling opera-tion.
In a preferred embodiment of this invention, theprocedure used to thermomechanically process the compact was to roll the compact for a 10 percent reduction in area, then anneal the rolled specimen. The reduction in area is carried out under a pressure that elongates the rolled specimen without substantially widening it. Generally, the annealing is carried out for a period of time and at a temperature sufficient to develop a specimen with a minimum creep rate. Preferably the annealing is carried out five minutes at l,900F (1,040C) before further rolling. The total extent of deformation ranges from 50 to 90 percent reduction in area and generally is approximately an 85 percent reduction in area. This roll/anneal cycle was selected to help develop a creep resistance micro-structure. The roll~anneal cycles are continued until the 85 percent reduction in area is accomplished.
There are several high-energy ball mills commercially available either using a stirrer or vibration .
.' ~!
ll'~t~ 't 1~311~A
_ ? _ 1 to induce mechanical alloyiny. Stainless steel bearings or grinding medid and th~ powder charye go into the cylindrical container of the mill. The high-energy impacts are affected by the rotating impeller. In the internal 5 arrangemellt of the attritor mill, ilnpact ~vents occur in the dynamic interstices of the media created by the impeller during stirring.
Dispersion-strengthened precious metals are known in the art and are commercially available. One such 10 material is that available from Johnson, Matthey ~ Co.
Limit~d, under their designation ZGS. The above indicated ZGS material consists essentially of platinum in which the disperoid is zirconia; the latter is present in an amount of about 0.5~ by volume.
The dispersion-strengthened precious metals of this invention generally comprise a precious metal, or precious metal alloy, preferably platinum, as the dispersing medium, or matrix, and a dispersoid of a metal oxide, metal carbide, metal silicide, meta1 nitride, metal 20 sulfide or a metal boride which dispersoid is present in effective dispersion-strengthening amounts. Usually such amounts will be between about 0.1 percent to about 5.0 percent by volume. Preferably the dispersoid will be an oxide. Exemplary of metal compounds which may be employed 25 as the dispersoid are compounds of metals of Group IIA, IIIA, IIIB (including non-hazardous metals of the Actinide and Lanthanide classes), IVB, VB, VIB and VIIB. ~lore specifically exemplary of suitable metals are the following: Be, Mg, Ca, Ba, Y, La, Ti, Ir, Hf, Mo, W, Ce, Nd, Gd, and Th as well as Al.
Several mechanical alloying experiments w~re performed using the attritor mill to g~nerate a composite powder for consolidation. ~ash heats intended to coat a thin layer of platinum on the internal working surfaces of 35 the attritor mill were carried out. This "conditioning"
treatment was intended to prevent iron contamination of subsequent milling experiments, but sQveral ~ashes were . ,~
., , .
:, -1~'7~'~5~
1.3118A
1 required before the iron contamination was reduced to what was be1ieved to be an acceptable level.
The samples then are consolidated by vacuum hot pressiny ~VHP) at elevated temperatures and pressur~s. In 5 the alternative, the samples can be consolidated by first cold pressing at elevated pressures followed by sint~ring at elevated tempera~ures. VHP generally is carried out at a temperature ranging from 1300 to 1700C under a pressure ranging from 500 to lU,000 psi for a time ranging from 10 10 to 30 minutes. Preferably, -the temperature ranges from 1400 to 1500C under a pressure of 3,00Q to 6,000 psi for a time of 15 to 25 minutes. Generally, the cold pressing is carried out at a pressure ranging from 2,000 to 10,000 psi for up to 5 minutes followed by sintering at a temperature 15 ranging from 1200 to 1700C for 2 to 6 hours.
EXAMPLE I
Approximately one kgm of -325 mesh (-44 micron) platinum sponge from Englehard was blended with an amount of yttria (Y203) to give nominally 0.65 volume percent 20 (0-15 weight percent) oxide loading in the final compact.
The yttri d was nominally 20G-600 angstrom in size. The platinum matrix starting powder for the experirnent consisted of very fine, near spherical particles or chained aggreg~tes. Most of the particles below 2 microns appeared 25 to be single crystals. The starting powder had a fairly high specific surface area.
The powder mixture WdS charged into the container of the attritor mill while it was running. The grinding media had been previously loaded to sive a volume 30 ratio of media to powder of 20:1. The grinding media used was a harderled 400 series stainless steel bearing nominally 3/8 inch ~0.953 cm) diameter. The impeller rotational speed was selected at 130 rpm.
Samples of powder were removed at various times 35 to obtain information on the changes in particle morphology and specific surface area wi~h milling time. The first `' 11'7~'~5~
A
1 sample was taken after one hour of milling and indicated that flake gtneration was in progress.
After milling For three hours, anotner pow(ler sample was taken for metallo-Jrdphic charact~rizdtiorl.
5 h'hile more flakes were generated, the extent o~ plastic defornlaticn seemed to hav~ increased. Flake cold w~lding appeared to have taken place as well. The composite flake appeared to tlaYe three or four component flakes cold welded together. No edge cracking appeared in the composite flake 10 suggesting that work nardening satura-tion hac not been reached at this point.
After milling for 23 hours, the composite flakes appeared to thicken. This clearly demonstrates the cold welding aspect of the milling action. Along with cold 15 welding, the flake diameter appeared to increase.
The experin,ent was continued for 71 hours then terminated, and the powder was removed for further processing.
There appeared to be a fairly high initial ' 20 surface area generation rate. The iron contamination in the milled po~lder was greatly reduced compared to the previous experiments and reflects the coating action that appeared to minimize wear debris generation during milling.
The maximum iron contamination level in the powder was 25 approximately ~00 wppm. The milled powder was consolidated by vacuum hot pressing and thermomechanically processing into sheet for creep testing, the details are to follow.
EXAMPLE II
_ Example I produced a powder of relatively lo~
30 iron contamination. Since this experiment resulted in small powder lots (nominally ~0 gms) taken at various times ~ during the milling experiment, each sample was individually - consolidated by vacuum hot pressing (VHP) at 1,450C under 5,000 psi (34.5 ~lN/m2) for twenty minutes. The resultant compacts were nominally 1 inch (2.54 cm) in diameter.
Relative density of specimerls are listed.
`'' A
~, 1 Specilllen ~illin~ Time (hr.) Relative Uensity (Uln) A 0 '~5.
l 9~.2 C 2.5 99.~, D 6 99.~3 The thermomechanical processing (TMP) used on the compact consisted of several roll/anneal cycles. The basic operation involved rolling a sheet specimen and cropping pieces after various rolling passes for microstructural 10 characterization. Tlle procedure used ~as to roll the compact for a 10 percent reduction in area then anneal the rolled specimen for five minutes at nominally 1,040C
before further rolling.
Specimen D was the most responsive to the TMP
15 cycles. After the 10th rolling pass, the grain structure was fairly elongated. The lack of oxide clusters during optical metallographic examination suggested that the milling action had worked the yttria into the platinum matrix. A metallographic analysis of the same region 20 sho~ed the development of a moderate grain aspect ratio (grain length to thickness ratio in the viewing plane). As the number of roll/anneal cycles increased, the grain aspect ratio (GAR) increased. At this stage a moderate GAR
also had been developed in a transverse direction. The 25 significance of this observation is that the grains took on the shape of a pancake structure thin in a direction perpendicular to the sheet yet extended in the other two directions. Since a GhR seems to extend in t~io directions in the rolled sheet and the state of stress in a bushing 30 tip plate is biaxial, this transv~rse GAR development may be very beneficial for good creep resistance in bushing applications.
After the 16th rolling pass, the elongation of the grains had increased significantly. A higher 35 magnification view of the same region revealed the degree !~ of yrain elongation and fineness of the grain size. The transverse GAR had also significantly increased. These - l -1 elon~ated grain morphologies are desirable microstructures for good creep resistance.
INDUSTRIAL APPLICABILITY
EXA~iPLE III
5 Creep Testing ~ ll thc creep testing was done in air usin~J
constant load machines the elongation was measured by an LVDT connected to a multi-point recorder and a precision digital voltmeter. Specimen temperature was monitored with 10 a calibrated Pt/Pt-Rh thermocouple attached so that the bead was adjacent to the gage section of the creep specimen. The creep specimen was a flat plate type wi-th a gage length of approximately 2.25 inch (5.72 cm). The tensile stress was applied parallel to the rolling 15 direction (longitudinal direction). The general procedure was to hang the specimen in th~ furnace to reach thermal equilibrium then start the rig timer upon application of the load. Periodic temperature and extension measurements were made either until the specimen failed or tne test was ; 20 t~rminated (specimen removal or furnace burn-out).
Creep results were obtained frum specimens that were processed according to Example II except that these specirnens ~lere milled 10 hours and received the above thermomechanical processing treatment of 10% reduction in 25 area per pass with an intermediate anneal at nominally 1040C for 5 ninutes. The extent of deformation was nominally an 85% reduction in area. The first specimen had a varied creep history that started by applying a tensile stress of 1 000 psi (6~89 ~In/m2) at 2 400F (1 316C). The 30 resultant secondary creep rate was too low to adequately measure; therefore the temperature was increased to
One of the most exacting applications of platinum is in the production of glass fibers. Molten glass often at temperatures ranging from 1200 to 1600C passes through a series of orifices in a bushing. Advances in glass fiber production are demanding both larger bushings and higher operating temperatures.
Structural components such as these at elevated tem-peratures under constant loads experience continuous dimension-al changes or creep during their lives. This creep behavior depends upon the interaction between the external conditions ~load, temperaturej and the microstructure of the component.
In recent times, increased resistance to creep of material systems has been accomplished by using a dispersion of very small, hard particles (called dispersoids) to strengthen the microstructure of the component. These systems have become to be known as dispersion-stre~gthened metals and alloys and the dispersoids used are usually oxides. A recent development in dispersion-strengthening is mechanical alloying which uses a high energy ball mill to achieve the intimate mechanical ; mixing typical of the process. An attritor mill or vibratory mill also can be used.
Accordingly, the present invention provides a process for producing sheets of a dispersion-strengthened precious - metal alloy which includes (1) platinum or a platinum alloy and (2) at least one metal oxide, comprising the step of .~
,, .
thermomechanically processing the compacted disperslon-strengthened precious metal alloy.
Preferably a series of mechanical deformation and annealing cycles are used to help develop a creep resistant microstructure. Specifically, this may be achieved by rolllng and annealing a powder compact of dispersion-strengthened pre-cious metal. The material may be cross-rolled as well as longitudinally rolled or just longitudinally rolled.
Figure 1 is a schematic drawing of the rolling opera-tion.
In a preferred embodiment of this invention, theprocedure used to thermomechanically process the compact was to roll the compact for a 10 percent reduction in area, then anneal the rolled specimen. The reduction in area is carried out under a pressure that elongates the rolled specimen without substantially widening it. Generally, the annealing is carried out for a period of time and at a temperature sufficient to develop a specimen with a minimum creep rate. Preferably the annealing is carried out five minutes at l,900F (1,040C) before further rolling. The total extent of deformation ranges from 50 to 90 percent reduction in area and generally is approximately an 85 percent reduction in area. This roll/anneal cycle was selected to help develop a creep resistance micro-structure. The roll~anneal cycles are continued until the 85 percent reduction in area is accomplished.
There are several high-energy ball mills commercially available either using a stirrer or vibration .
.' ~!
ll'~t~ 't 1~311~A
_ ? _ 1 to induce mechanical alloyiny. Stainless steel bearings or grinding medid and th~ powder charye go into the cylindrical container of the mill. The high-energy impacts are affected by the rotating impeller. In the internal 5 arrangemellt of the attritor mill, ilnpact ~vents occur in the dynamic interstices of the media created by the impeller during stirring.
Dispersion-strengthened precious metals are known in the art and are commercially available. One such 10 material is that available from Johnson, Matthey ~ Co.
Limit~d, under their designation ZGS. The above indicated ZGS material consists essentially of platinum in which the disperoid is zirconia; the latter is present in an amount of about 0.5~ by volume.
The dispersion-strengthened precious metals of this invention generally comprise a precious metal, or precious metal alloy, preferably platinum, as the dispersing medium, or matrix, and a dispersoid of a metal oxide, metal carbide, metal silicide, meta1 nitride, metal 20 sulfide or a metal boride which dispersoid is present in effective dispersion-strengthening amounts. Usually such amounts will be between about 0.1 percent to about 5.0 percent by volume. Preferably the dispersoid will be an oxide. Exemplary of metal compounds which may be employed 25 as the dispersoid are compounds of metals of Group IIA, IIIA, IIIB (including non-hazardous metals of the Actinide and Lanthanide classes), IVB, VB, VIB and VIIB. ~lore specifically exemplary of suitable metals are the following: Be, Mg, Ca, Ba, Y, La, Ti, Ir, Hf, Mo, W, Ce, Nd, Gd, and Th as well as Al.
Several mechanical alloying experiments w~re performed using the attritor mill to g~nerate a composite powder for consolidation. ~ash heats intended to coat a thin layer of platinum on the internal working surfaces of 35 the attritor mill were carried out. This "conditioning"
treatment was intended to prevent iron contamination of subsequent milling experiments, but sQveral ~ashes were . ,~
., , .
:, -1~'7~'~5~
1.3118A
1 required before the iron contamination was reduced to what was be1ieved to be an acceptable level.
The samples then are consolidated by vacuum hot pressiny ~VHP) at elevated temperatures and pressur~s. In 5 the alternative, the samples can be consolidated by first cold pressing at elevated pressures followed by sint~ring at elevated tempera~ures. VHP generally is carried out at a temperature ranging from 1300 to 1700C under a pressure ranging from 500 to lU,000 psi for a time ranging from 10 10 to 30 minutes. Preferably, -the temperature ranges from 1400 to 1500C under a pressure of 3,00Q to 6,000 psi for a time of 15 to 25 minutes. Generally, the cold pressing is carried out at a pressure ranging from 2,000 to 10,000 psi for up to 5 minutes followed by sintering at a temperature 15 ranging from 1200 to 1700C for 2 to 6 hours.
EXAMPLE I
Approximately one kgm of -325 mesh (-44 micron) platinum sponge from Englehard was blended with an amount of yttria (Y203) to give nominally 0.65 volume percent 20 (0-15 weight percent) oxide loading in the final compact.
The yttri d was nominally 20G-600 angstrom in size. The platinum matrix starting powder for the experirnent consisted of very fine, near spherical particles or chained aggreg~tes. Most of the particles below 2 microns appeared 25 to be single crystals. The starting powder had a fairly high specific surface area.
The powder mixture WdS charged into the container of the attritor mill while it was running. The grinding media had been previously loaded to sive a volume 30 ratio of media to powder of 20:1. The grinding media used was a harderled 400 series stainless steel bearing nominally 3/8 inch ~0.953 cm) diameter. The impeller rotational speed was selected at 130 rpm.
Samples of powder were removed at various times 35 to obtain information on the changes in particle morphology and specific surface area wi~h milling time. The first `' 11'7~'~5~
A
1 sample was taken after one hour of milling and indicated that flake gtneration was in progress.
After milling For three hours, anotner pow(ler sample was taken for metallo-Jrdphic charact~rizdtiorl.
5 h'hile more flakes were generated, the extent o~ plastic defornlaticn seemed to hav~ increased. Flake cold w~lding appeared to have taken place as well. The composite flake appeared to tlaYe three or four component flakes cold welded together. No edge cracking appeared in the composite flake 10 suggesting that work nardening satura-tion hac not been reached at this point.
After milling for 23 hours, the composite flakes appeared to thicken. This clearly demonstrates the cold welding aspect of the milling action. Along with cold 15 welding, the flake diameter appeared to increase.
The experin,ent was continued for 71 hours then terminated, and the powder was removed for further processing.
There appeared to be a fairly high initial ' 20 surface area generation rate. The iron contamination in the milled po~lder was greatly reduced compared to the previous experiments and reflects the coating action that appeared to minimize wear debris generation during milling.
The maximum iron contamination level in the powder was 25 approximately ~00 wppm. The milled powder was consolidated by vacuum hot pressing and thermomechanically processing into sheet for creep testing, the details are to follow.
EXAMPLE II
_ Example I produced a powder of relatively lo~
30 iron contamination. Since this experiment resulted in small powder lots (nominally ~0 gms) taken at various times ~ during the milling experiment, each sample was individually - consolidated by vacuum hot pressing (VHP) at 1,450C under 5,000 psi (34.5 ~lN/m2) for twenty minutes. The resultant compacts were nominally 1 inch (2.54 cm) in diameter.
Relative density of specimerls are listed.
`'' A
~, 1 Specilllen ~illin~ Time (hr.) Relative Uensity (Uln) A 0 '~5.
l 9~.2 C 2.5 99.~, D 6 99.~3 The thermomechanical processing (TMP) used on the compact consisted of several roll/anneal cycles. The basic operation involved rolling a sheet specimen and cropping pieces after various rolling passes for microstructural 10 characterization. Tlle procedure used ~as to roll the compact for a 10 percent reduction in area then anneal the rolled specimen for five minutes at nominally 1,040C
before further rolling.
Specimen D was the most responsive to the TMP
15 cycles. After the 10th rolling pass, the grain structure was fairly elongated. The lack of oxide clusters during optical metallographic examination suggested that the milling action had worked the yttria into the platinum matrix. A metallographic analysis of the same region 20 sho~ed the development of a moderate grain aspect ratio (grain length to thickness ratio in the viewing plane). As the number of roll/anneal cycles increased, the grain aspect ratio (GAR) increased. At this stage a moderate GAR
also had been developed in a transverse direction. The 25 significance of this observation is that the grains took on the shape of a pancake structure thin in a direction perpendicular to the sheet yet extended in the other two directions. Since a GhR seems to extend in t~io directions in the rolled sheet and the state of stress in a bushing 30 tip plate is biaxial, this transv~rse GAR development may be very beneficial for good creep resistance in bushing applications.
After the 16th rolling pass, the elongation of the grains had increased significantly. A higher 35 magnification view of the same region revealed the degree !~ of yrain elongation and fineness of the grain size. The transverse GAR had also significantly increased. These - l -1 elon~ated grain morphologies are desirable microstructures for good creep resistance.
INDUSTRIAL APPLICABILITY
EXA~iPLE III
5 Creep Testing ~ ll thc creep testing was done in air usin~J
constant load machines the elongation was measured by an LVDT connected to a multi-point recorder and a precision digital voltmeter. Specimen temperature was monitored with 10 a calibrated Pt/Pt-Rh thermocouple attached so that the bead was adjacent to the gage section of the creep specimen. The creep specimen was a flat plate type wi-th a gage length of approximately 2.25 inch (5.72 cm). The tensile stress was applied parallel to the rolling 15 direction (longitudinal direction). The general procedure was to hang the specimen in th~ furnace to reach thermal equilibrium then start the rig timer upon application of the load. Periodic temperature and extension measurements were made either until the specimen failed or tne test was ; 20 t~rminated (specimen removal or furnace burn-out).
Creep results were obtained frum specimens that were processed according to Example II except that these specirnens ~lere milled 10 hours and received the above thermomechanical processing treatment of 10% reduction in 25 area per pass with an intermediate anneal at nominally 1040C for 5 ninutes. The extent of deformation was nominally an 85% reduction in area. The first specimen had a varied creep history that started by applying a tensile stress of 1 000 psi (6~89 ~In/m2) at 2 400F (1 316C). The 30 resultant secondary creep rate was too low to adequately measure; therefore the temperature was increased to
2 600F (1 427C) and a secondary creep rate of ~;.5xlO 6 hr~l was observed. After approximately 118 hours ths i stress ~las increased to 1 400 psi (9.65 Mn/nl2) and a new ,econdary creep rate of nominally 3xlO 5 hr 1 was recorded.
Th~se creep rates dre t~io orders of magni~ude l~ss than that for the previously indicated 7GS under the same 5'3 1 testing conditions. The Z~S rnaterial will have a stress rupture life of at least 4~ hours when tested at 140U C and 1000 psi in the rolling direction of th~ sheet.
The general microstructure of the crept sp~cimfn S indicated that the grains were highly elongated in the rolling direction (creep stress direction also) ~nd the grain boundries were ragged. There appPared -to be evidence o~ subgrains in the structure as well. The microstructure observed in this specimen was typical of that of a good 10 creep resistant material as èvidenced by the exceptionally good creep properties.
, .
..
1' :
. ,
Th~se creep rates dre t~io orders of magni~ude l~ss than that for the previously indicated 7GS under the same 5'3 1 testing conditions. The Z~S rnaterial will have a stress rupture life of at least 4~ hours when tested at 140U C and 1000 psi in the rolling direction of th~ sheet.
The general microstructure of the crept sp~cimfn S indicated that the grains were highly elongated in the rolling direction (creep stress direction also) ~nd the grain boundries were ragged. There appPared -to be evidence o~ subgrains in the structure as well. The microstructure observed in this specimen was typical of that of a good 10 creep resistant material as èvidenced by the exceptionally good creep properties.
, .
..
1' :
. ,
Claims (15)
1. A process for producing sheets of a dispersion-strengthened precious metal alloy which includes (1) platinum or a platinum alloy and (2) at least one metal oxide, com-prising the step of thermomechanically processing the compacted dispersion-strengthened precious metal alloy.
2. A process according to claim 1 wherein the thermo-mechanical processing comprises at least one mechanical deform-ing/annealing cycle and the cycles are repeated until a 50 to 90 percent reduction in area is achieved.
3. A process according to claim 2 wherein the mecha-nical deforming is rolling.
4. A process according to claim 2 wherein mechanical deforming is carried out until a 10 percent reduction in area is achieved before the compact is annealed.
5. A process according to claim 4 wherein the re-duction in area is carried out at a pressure that elongates the compact without widening it.
6. A process according to claim 2 or 3 wherein the mechanical deforming/annealing cycles are carried out until approximately an 85 percent reduction in area is achieved.
7. A process according to claim 1 wherein the metal oxide is yttria (Y2O3).
8. A process according to claim 1 wherein the dis-persion-strengthened precious metal alloy is produced by mecha-nical alloying.
9. A process for producing sheets of a dispersion-strengthened precious metal alloy which includes (1) platinum or a platinum alloy and (2) at least one metal oxide, com-prising a series of rolling/annealing cycles wherein each annealing step is carried out for a period of time and at a temperature sufficient to develop a specimen with a minimum creep rate.
10. A process for producing sheets of a dispersion-strengthened precious metal alloy comprising the steps of:
(1) mechanically alloying platinum powder and yttria (Y2O3) together wherein the yttria is present in an effective dispersion-strengthening amount;
(2) consolidating the resulting powder by vacuum hot pressing at elevated temperature and pressure and (3) carrying out a series of rolling/annealing cycles wherein each annealing step is carried out for a period of time and at a temperature sufficient to develop a specimen with a minimum creep rate.
(1) mechanically alloying platinum powder and yttria (Y2O3) together wherein the yttria is present in an effective dispersion-strengthening amount;
(2) consolidating the resulting powder by vacuum hot pressing at elevated temperature and pressure and (3) carrying out a series of rolling/annealing cycles wherein each annealing step is carried out for a period of time and at a temperature sufficient to develop a specimen with a minimum creep rate.
11. A process according to claim 9 wherein the metal oxide is yttria (Y2O3).
12. A process according to claim 10 or 11 wherein the amount of yttria ranges between 0.1 to 5.0 percent by volume.
13. A process according to claim 10 or 11 wherein the amount of yttria is 0.65 percent by volume.
14. A process according to claim 10 wherein the vacuum hot pressing is carried out at a temperature of about 1,450°C under a pressure of about 5,000 psi for a time of about twenty minutes and the annealing is carried out for about 5 minutes at about 1040°C.
15. A process according to claim 10 wherein high energy ball milling is used to achieve the mechanical alloying.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US8172279A | 1979-10-04 | 1979-10-04 | |
| US081,722 | 1979-10-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178459A true CA1178459A (en) | 1984-11-27 |
Family
ID=22165974
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000360277A Expired CA1178459A (en) | 1979-10-04 | 1980-09-16 | Thermomechanical processing of dispersion- strengthened precious metal alloys |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS56501457A (en) |
| CA (1) | CA1178459A (en) |
| GB (1) | GB2075552A (en) |
| SE (1) | SE8103481L (en) |
| WO (1) | WO1981001013A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4536202A (en) * | 1983-12-06 | 1985-08-20 | Owens-Corning Fiberglas Corporation | Drain bushing |
| US4518406A (en) * | 1983-12-06 | 1985-05-21 | Owens-Corning Fiberglas Corporation | Drain bushing |
| US4819859A (en) * | 1987-12-18 | 1989-04-11 | Ppg Industries, Inc. | Lamination of oxide dispersion strengthened platinum and alloys |
| DE10046456C2 (en) * | 2000-09-18 | 2003-04-10 | Heraeus Gmbh W C | Through finely divided, small particles of base metal oxide, dispersion-strengthened, gold-free platinum material |
| DE102013225187B4 (en) | 2013-12-06 | 2018-07-19 | Heraeus Deutschland GmbH & Co. KG | Method for processing a dispersion-hardened platinum composition |
| EP3971311B1 (en) | 2020-09-17 | 2022-07-06 | Heraeus Deutschland GmbH & Co. KG | Improved dispersion-hardened precious metal alloy |
| EP3978884B1 (en) | 2020-10-02 | 2024-05-29 | Heraeus Precious Metals GmbH & Co. KG | Wire with platinum composition for contacting temperature sensors |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA801702A (en) * | 1968-12-17 | W. Fraser Robert | Working cycle for dispersion strengthened materials | |
| GB1134492A (en) * | 1964-03-11 | 1968-11-27 | Johnson Matthey Co Ltd | Methods of improving the mechanical properties of metals and their alloys |
| GB1139897A (en) * | 1965-01-15 | 1969-01-15 | Johnson Matthey Co Ltd | Improvements in and relating to the treatment of platinum group metals and alloys |
| US3738817A (en) * | 1968-03-01 | 1973-06-12 | Int Nickel Co | Wrought dispersion strengthened metals by powder metallurgy |
-
1980
- 1980-08-18 GB GB8112099A patent/GB2075552A/en not_active Withdrawn
- 1980-08-18 WO PCT/US1980/001062 patent/WO1981001013A1/en unknown
- 1980-08-18 JP JP50222980A patent/JPS56501457A/ja active Pending
- 1980-09-16 CA CA000360277A patent/CA1178459A/en not_active Expired
-
1981
- 1981-06-03 SE SE8103481A patent/SE8103481L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| GB2075552A (en) | 1981-11-18 |
| JPS56501457A (en) | 1981-10-08 |
| WO1981001013A1 (en) | 1981-04-16 |
| SE8103481L (en) | 1981-06-03 |
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