Contents Powder metallurgy

Above 40 wt % hydrogen content at room temperature, zirconium hydride is brittle, ie, has no tensile ductiHty, and it becomes more friable with increasing hydrogen content. This behavior and the reversibiHty of the hydride reaction are utilized ki preparing zirconium alloy powders for powder metallurgy purposes by the hydride—dehydride process. The mechanical and physical properties of zirconium hydride, and thek variation with hydrogen content of the hydride, are reviewed in Reference 127. 

Powder Metallurgy. The content of this article is 3 verbatim reproduction of the ref ... 

Production. Powder metallurgy is the only viable way to produce composites of high quality. The method of production depends on the composition ratio. Materials with 10 to 40 wt% copper (20 to 50 wt% silver) are commonly produced by infiltration, while at higher copper or silver contents the powders are blended, pressed, and subsequently solid-state sintered [6.42,6.46]. 

The latter steels have been developed during the last few decades. (For compositions, properties and standard numbers, see Table 10.6.) A benefit of the ferritic-austenitic steels is their higher strength compared with the austenitic. Ferritic-austenitic 25-7-4 steel and austenitic 20-18-6 have both shown very good crevice corrosion properties in seawater, but also on these steels attacks may develop when the temperature is above a limit that depends on various conditions. Of these two steel types, the ferritic-austenitic steel may have somewhat lower corrosion resistance in welds than the austenitic 6 Mo steel. With first-class welds, pipes made of the latter material are considered safe to use up to 30-35°C in seawater. However, on flanges that are cast or produced by powder metallurgy, attacks have been found at a temperature as low as 10-15°C. For use in chlorinated seawater with a residual chlorine content of 1.5 ppm, the NORSOK standard [10.10] recommends a maximum temperature of 15°C for components with crevices and 30°C for... 

Carbon fiber can also be mixed with metal powders (powder metallurgy), degassed, preferably canned and then heated under pressure (50 MPa) at about 760°C, limiting the fiber content to about 25% by the use of excessive pressure. 

Furthermore, considering the results obtained by Vandecasteele et al. (79), it is clear that carbon contents as low as this are observable in industrial molybdenum and tungsten prepared by powder metallurgy. 

Tak] Takagi, K., Komai, M., Ide, T, Watanabe, T, Kondo, Y, Effects of Mo and Cr Contents on the Properties and Phase Formation of Iron Molybdenum Boride Base Hard Alloys , Powder Metallurgy International, 19(5), 30-33 (1987) (Crys. Stracture, Morphology, Phase Relations, Experimental, Meehan. Prop., 13)... 

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