| 摘要 |
Powder metallurgical prodn. of a finished article of a beta brass-type, metal oxide dispersoid-contg., copper-rich shape memory alloy comprises (a) melting an alloy, contg. all the components in the desired stoichiometric ratios with a tolerance of less than 0.1 wt.% for Al, less than 0.5 wt.% for Cu and Zn and less than 0.2 wt.% for Ni, under vacuum or protective gas atmos.; (b) tapping the alloy under vacuum or protective gas atmos. and transferring to a high disintegration effect, pressure pulse, (ultra-)sonic atomising device under protective gas with adjustable O2 content; (c) atomising the molten alloy stream in a protective gas atmos. contg..1-2 vol.% O2 and producing a homogeneous powder of globular particles of diameter 5-70 microns, at least 40 wt.% being of 25 microns diameter, by cooling at more than 1000 deg.C/sec.; (d) (thermo-) mechanically compacting the powder to a blank or semi-finished profile; and (e) separating an article from the blank or profile and (thermo-) mechanically processing to a finished article by hot pressing, forging, hot rolling, hot drawing and/or cold pressing, cold rolling, cold drawing and machining. ADVANTAGE - Inexpensive shape memory articles with reproducible physical and mechanical properties are produced.
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