Powder metallurgy processes – Powder metallurgy processes with heating or sintering – Powder pretreatment
Patent
1999-03-09
1999-11-02
Jenkins, Daniel J.
Powder metallurgy processes
Powder metallurgy processes with heating or sintering
Powder pretreatment
419 29, 419 38, 419 47, 419 57, 148513, B22F 100, B22F 312
Patent
active
059764562
ABSTRACT:
This invention relates to a method for producing sintered parts of aluminum or aluminum alloy with improved mechanical properties using batch degassing, die compaction and liquid phase sintering. The batch degassing consists of holding a prealloyed aluminum powder at a temperature of about 350.degree. to about 450.degree. C. in a stainless steel autoclave in which the pressure is reduced to less than 5.times.10.sup.-6 torr. Once the desired pressure is reached the powder is cooled down within the autoclave while still under vacuum. The resulting powder is then compacted at a pressure of 20 to 50 tsi at between room temperature and about 250.degree. C., but preferably at a warm temperature of about 65.degree. C. The final densification is completed by liquid phase sintering in argon atmosphere at 625.degree. C. This method allows the production of sintered compacts characterized by a density close to 97% of theoretical, which makes it possible to eliminate the need for a hot working step.
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Pelletier Sylvain
Ziani Abdelouahab
Jenkins Daniel J.
National Research Council of Canada
Rock H. Wayne
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