A single step is relied on in the canning process for hot isostatic pressing (HIP) metallurgy composites. The composites are made from arc sprayed and plasma sprayed monotape. The HIP can is of compatible refractory metal and is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing

Juhas, John J.

English

NASA Technical Reports Server

United States Patent [191 [ i l l  Patent Number: 4,980,126 
Juhas [451 Date of Patent: Dec. 25, 1990 
[54] PROCESS FOR HIP CANNING OF 
COMPOSITES 
[75] Inventor: John J. Juhas, Columbia Station, 
[73] Assignee: The United States of America as 
Ohio 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. NO.: 433,863 
[22] Filed: Nov. 9, 1989 
Related U.S. Application Data 
[63] Continuation-in-part of Ser. No. 326,757, Mar. 21, 
1989, Pat. No. 4,904,538. 
[51] Int. ( 3 . 5  ................................................ B22F 3/14 
[52] U.S. Cl. .......................................... 419/49; 419/8; 
419/24; 419/36; 419/37; 419/48; 419/54; 
419/60; 428/552 
Field of Search ................... 419/8, 24, 36, 37, 48, 
419/49, 54, 60; 428/552, 551 
[58] 
[561 References Cited 
US. PATENT DOCUMENTS 
3,714,702 2/1973 Hammond ............................. 29/494 
3,940,268 2/1976 
4,104,782 8/1978 
4,110,131 8/1978 
4,212,669 7/1980 
4,335,192 6/1982 
4,448,747 5/1984 
4,554,130 11/1985 
4,587,096 5/1986 
4,599,215 7/1986 
4,673,549 6/1987 
4,871,621 10/1989 
4,904,538 2/1990 
Catlin .................................... 491/49 
Veeck et al. ....................... 29/527.2 
Gessinger .. 14W11.5 N 
Veeck et al. .......................... 75/226 
Oliapuram ............................ 419/37 
Moritoki et a1 4 19/49 
Ecer 4 19/8 
Mankins et al. ...................... 419/27 
Smarsly et al. ....................... 419/42 
Ecer ...................................... 419/10 
Bagley et al. 428/549 
Juhas ................................... 428/552 
Primary Examiner-Stephen J. Lechert, Jr. 
Assistant Examiner-Ngoclan Mai 
Attorney, Agent, or Firm-Gene Shook; James A. 
Mackin; John R. Manning 
1571 ABSTRACT 
A single step is relied on in the canning process for hot 
isostatic pressing metallurgy composites. The compos- 
ites are made from arc-sprayed and plasma sprayed 
monotape. The HIP can is of compatible refractory 
metal and is sealed at high vacuum and temperature. 
This eliminates out-gassing during hot isostatic press- 
ing. 
12 Claims, 3 Drawing Sheets 
12 
https://ntrs.nasa.gov/search.jsp?R=19910007832 2020-03-24T06:43:32+00:00Z
US. Patent Dec. 25,1990 Sheet 1 of 3 4,980,126 
12 
14 
7 
10 
FIG. 1 
US. Patent DN. 25,1990 Sheet 2 of 3 4,980,126 
f"" 
24. 
FIG. 2 
U.S. Patent DW. 25,1990 Sheet 3 of 3 4,980,126 
G50 
30 \ ,20 
38 
l t l  
/-54 
V 
FIG. 3 
1 
4,980,126 
I 
PROCESS FOR HIP CANNING OF COMPOSITES 
ORIGIN OF THE INVENTION 
The invention described herein was made by an em- 
ployee of the United States Government and may be 
manufactured and used by or for the Government for 
governmental purposes without the payment of any 
royalties thereon or therefore. 
STATEMENT OF COPENDENCY 
This application is a continuation-in-part of applica- 
tion Ser. No. 326,757 which was filed Mar. 21, 1989, and 
issued as US. Pat. No. 4,904,538 
TECHNICAL FIELD 
This invention is directed to an improved process for 
canning composites. The invention is particularly con- 
cerned with canning composites made from arc sprayed 
and plasma sprayed monotape. 
One conventional method for canning a specimen for 
hot isostatic pressing is to lay up the specimen in a 
refractory metal can that is electron beam welded 
closed in a vacuum. This can with the vacuum sealed 
inside is then ready for hot isostatic pressing. 
The main disadvantage to this process is that the 
vacuum in the can is sealed in at room temperature and 
subsequent heating in the HIP operation can cause out- 
gassing in the canned specimen. This results in poor 
densification, and in certain specimens this residual gas 
will react with the specimen degrading the materials 
properties. This is especially a problem with arc- 
sprayed and plasma sprayed composite monotapes be- 
cause their rough surfaces tend to trap contaminants. 
place in the furnace while the furnace is located in a 
chamber under vacuum. 
Ecer U.S. Pat. No. 4,554,130 describes a method of 
consolidation of a part from separate metallic compo- 
5 nents. A binder is burned off at elevated temperatures, 
and pressure is used to consolidate the powdered metal. 
Ecer U.S. Pat. No. 4,673,549 discloses a method for the 
manufacture of objects by the .consolidation of pow- 
dered metals and the like. A metal or ceramic can holds 
lo a shaped shell. The shell, as well as the space between 
the shell and can, are both filled with powder. The can 
is then out-gassed and sealed. Pressing is used to consol- 
idate the powder into a dense form. 
Smarsly et a1 U.S. Pat. No. 4,599,215 discloses a 
method for producing compressed moldings from loose 
or sintered metal powder. A flow die is compressed in a 
cavity block to thereby compress metal powder con- 
tained in a hermetically sealed capsule. 
20 DISCLOSURE OF THE INVENTION 
The objects of the invention are achieved by a single 
step hot isostatic pressing (HIP) canning of composite 
specimens made from arc-sprayed and plasma sprayed 
25 monotape. Each specimen is placed inside of a refrac- 
tory metal ring and sandwiched between two refractory 
metal sheets. The resultant assembly is placed in a die 
which is loaded in a hot vacuum press. The temperature 
is raised in the vacuum to remove trapped residual gas 
The temperature and pressure are raised to values 
sufficient to cause deformation of the refractory metal 
ring and a solid state diffusion weld to occur between 
the ring and the face sheets. This deformation continues 
30 and burn off contaminants. 
Also, their porous nature makes it very difficult to thor- 35 until the composite specimen partially densifies, thereby 
oughly remove all the air during a standard canning locking the specimen geometry in place. A perfectly 
process. fitted, clean, out-gassed HIP can sealed at high tempera- 
Inasmuch as the can is electron beam welded there is ture and vacuum has now been created. The optimum 
a potential for cracks in the welds due to the recrystalli- situation now exists to complete the densification of the 
zation of the refractory metal in the heat-affected weld 40 specimen by HIPPING. 
zone. This cracking of the weld prevents the specimen 
from densifying in the HIP operation. DESCRIPTION OF THE DRAWINGS 
Another disadvantage is that the HIP cans have to be me objects, advantages and novel features of the 
variations in the specimen's dimensions, these cans can- 45 ing detailed description when read in connection with 
not be a perfect fit. As deformation of the can occurs in the accompanying drawings wherein like numerals are 
the HIP operation, uneven stresses can occur causing used throughout to identify like parts. 
FIG. 1 is a perspective view showing a specimen warping of the specimen. It is, therefore, an object of the present invention to with the required component parts of the provide a one step, ideal, and economical method of 50 
canning composites made from arc-sprayed and plasma FIG. 2 is a schematic view showing the assembly of sprayed monotape. 
BACKGROUNDART FIG. 3 is a schematic view showing the die of FIG. 2 
disclose methods for consolidating precision shapes 
wherein powder particles are consolidated into shaped 
porous preforms. Coatings are applied to these preforms 
which are &gasified by a vacuum at elevated tempera- Referring now to FIG. 1, there is shown an assembly 
tures. The coated preforms are heated under a vacuum 60 10 f(X'med in accordance with the Present invention. A 
formed to the approximate size ofthe specimen. Due to invention will be more fully apparent from the follow- 
present invention; 
FIG. 1 positioned in a channel die; and 
Veeck et al US. Pat. Nos. 4,104,782 and 4,212,669 55 positioned in a hot vacuum press' 
DETAILED DESCRIPTION OF THE 
INVENTION 
to a temperature such that the coating is densified to the specimen 12 comprising layers of Xc-sPraYed and 
extent that it becomes non-porous. plasma sprayed monotape is positioned within a metal 
Gessinger US.  Pat. No. 4,110,131 describes the pow- ring Or frame 14 which is interposed between a Pair of 
der metallurgic production of a high temperature alloy face sheets 16 and 18. 
body. Moritoki et a1 U.S. Pat. No. 4,448,747 discloses a 65 The monotape in the specimen 12 may be made in 
high density sintering method for powder molded prod- accordance with the teachings of U.S. Pat. No. 
ucts wherein the products are loaded into a heating 4,518,625 to Westfall. The ring 14 and the face sheets 16 
furnace. Preliminary sintering of the products takes and 18 are of a refractory metal. 
4,980,126 
3 
The assembly 10 is placed in a molybdenum channel 
die 20 as shown in FIG. 2. More particularly, the speci- 
men assembly 10 is positioned between a pair of pres- 
sure plates 22 and 24 that are located between a pair of 
spaced knockout wedges 26 and 28. 
A punch 30 is mounted for reciprocating motion 
between the wedges 26 and 28. The outermost end of 
the punch 30 engages the surface of the pressure plate 
22 that is opposite the face which engages the specimen 
assembly 10. A thermocouple 32 is provided in the 
pressure plate 22, while a similar thermocouple 34 is 
mounted in the opposite pressure plate 24. 
The channel die 20 with the specimen assembly 10 
therein is mounted in a hot press 36 that is contained in 
a vacuum chamber 38 as shown in FIG. 3. More partic- 
ularly, the hot press 36 utilizes an induction coil 40 
which surrounds the die 20 that is supported by a mo- 
lybdenum pedestal 42. A stainless steel bellows 44 encir- 
cles the pedestal 42 to maintain the vacuum environ- 
ment. The temperature is raised to a vaIue sufficiently 
high, in a high vacuum atmosphere, to cause any 
trapped residual gas to leave the specimen, and any 
contaminants to “bum off’ leaving a completely clean 
outgassed specimen. 
Insulation 46 in the form of zirconia sheets thermally 
isolates the die 20 from the pedestal 42. Likewise, insu- 
lation 48 in the form of similar zirconia sheets thermally 
isolates the punch 20 from a steel ram 50 on a press 52. 
The pedestal 42 is carried by base 54 which is opposite 
the press 52. This base is capable of supporting loads up 
to 250,000 lbs. as indicated by the arrows in FIG. 3. 
The specimen assembly 10 is heated in the vacuum 38 
by the coils 40 to an elevated temperature. Load is 
applied by the press 52 through the steel ram 50 and 
punch 30. The temperature and pressure are raised to 
values sufficient to cause deformation of the refractory 
metal ring 14. 
A solid state diffusion weld occurs between the ring 
14 and the face sheets 16 and 18. This deformation con- 
tinues until the composites specimen 12 partially densi- 
fies. This locks the specimen geometry in place. 
A perfectly fitted, clean, outgassed HIP can sealed at 
high temperature and vacuum has been created. The 
optimum situation now exists to complete the densifica- 
tion of the specimen by HIPPING. 
It will be appreciated by those skilled in the art that 
the novel process provides for the sealing of the com- 
posite in the HIP can of compatible refractory metal in 
a single operation. This eliminates the extra cost of 
forming and electron beam welding separate HIP cans. 
Also, the HIP cans are sealed at high vacuum and at 
high temperature thereby assuring no outgassing will 
occur during the HIP process. This is important as 
out-gassing inside the can would prevent complete den- 
sification and could cause interstitial contamination 
leading to embrittlement of the specimen. The geome- 
try and uniformity of the specimen are maintained due 
to the optimum fitting HIP can. This prevents specimen 
warpage caused by uneven stresses that can occur in 
conventional HIP canning procedures. 
Because it is not necessary to electron beam weld the 
HIP can, recrystallization of the weld area does not 
occur. This eliminates the possibility of a cracking fail- 
ure of the can. The cost and labor of duplicating failed 
specimens are saved. 
While the preferred embodiment of the invention has 
been shown and described, it will be appreciated in 
various structural and procedural modifications may be 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
55 
60 
65 
4 
made without departing from the spirit of the invention 
and the scope of the subjoined claims. By way of exam- 
ple, because of compatibility differences between speci- 
men material and the rings and face sheets, different 
refractory materials can be used with equal success. 
I claim: 
1. A method of canning a composite formed from a 
sprayed porous monotape having trapped contaminants 
and gas prior to hot isostatic pressing comprising the 
steps of 
enclosing said composite with a metal frame adjacent 
the outer peripheral surface thereof, 
interposing said composite and frame between spaced 
face sheets to form an assembly, 
positioning said assembly in a die, 
loading said die and assembly into a vacuum hot 
press, 
heating said composite in a vacuum to a first tempera- 
ture, sufficiently high to cause trapped gas to leave 
the composite and contaminants to bum off, 
maintaining said composite at said first temperature 
while applying a pressure load to said die, 
heating said composite to a second temperature that is 
substantially higher than said first temperature 
while increasing said pressure load, said second 
temperature and pressure being raised to values 
sufficient to deform said metal frame, 
maintaining said composite at said second tempera- 
ture while deforming said frame and producing a 
solid state diffusion weld between said frame and 
said face sheets, and 
partially densifying said composites thereby establish- 
ing the geometry of the same. 
2. A method of canning a composite as claimed in 
claim 1 wherein said frame comprises a refractory metal 
ring. 
3. A method of canning a composite as claimed in 
claim 2 wherein said monotape is arc-sprayed. 
4. A method of canning a composite as claimed in 
claim 2 where said monotape is plasma sprayed. 
5. In a method of hot isostatic pressing a metallurgy 
composite comprising porous sprayed monotape having 
trapped contaminants and gas, an improved canning 
process including 
heating said composite between face plates separated 
by a frame that surrounds said monotape to cause 
trapped gas to leave the composite and contami- 
nants to bum off, and 
applying a pressure load to said composite in a vac- 
uum at a higher temperature at which the frame is 
deformed and a solid state diffusion weld is pro- 
duced between said face plates and said frame 
thereby partially densifying said composite to lock 
the monotape in place in a can. 
6. A method of hot isostatic pressing a metallurgy 
composite as claimed in claim 5 wherein said frame and 
said face plates are metal. 
7. A method of hot isostatic pressing a metallurgy 
composite as claimed in claim 6 wherein said frame and 
face plates are a refractory metal. 
8. A method of hot isostatic pressing a metallurgy 
composite as claimed in claim 5 wherein the frame is 
deformed and the solid state diffusion weld is formed by 
applying a pressure load to said face plates. 
9. A method of hot isostatic pressing a metallurgy 
composite as claimed in claim 8 wherein the pressure 
load is applied to a die carrying said composite. 
4,980,126 
5 6 
to seal the same so that no out-gassing will occur 
subsequent during hot isostatic pressing. 
11. An improved method as claimed in claim 10 in- 
deforming the can at an elevated temperature to pro- 
duce a solid state diffusion weld around said com- 
posite. 
10. In a method of hot isostatic pressing a metallurgy 
composite containing Porous sprayed monotape, an 
improved canning process comprising 
enclosing said composite in a can, 
removing trapped residual gas while burning off con- 
c 1 u d i n g 
5 
taminants from said enclosed composite, and 12. An improved method as claimed in claim 11 
wherein the can is deformed by applying the pressure 
load. raising the temperature of said composite while si- 
multaneously applying a pressure load to said can * * * * *  
15 
20 
25 
30 
35 
40 
45 
50 
55 
60 
65 


Process for HIP canning of composites

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server