Wenge LIU+
,
Min ZHU
,
Dazhi YANG
,
Dept. of Materials Engineering
,
Dalian University of Technology
,
Dalian
,
116024
,
ChinaZhongguang WANG
,
State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
11001
材料科学技术（英）
The thermal-mechanical (T-M) cycles at constant strain of a polycrystalline CuZnAl alloy have been studied in the. present work. In-situ optical microscopic observations have been made to reveal the features of the phase transitions during T-M cycling. The variation of stress-temperature (S-T) curves and electrical resistance-temperature (R-T) curves accompanying with T-M cycling have been measured by tensile test and electrical resistance measurements. It has been found that the polycrystalline CuZnAl alloy shows apparent morphology changes and properties variations in the first cycle during T-M cycling which is called the first cycle effect in the present work. The stable transformation procedure in the T-M cycle is: martensiteparent phase +residual acicular martensite. This residual martensite possesses the character of stress-induced martensite.
关键词:
CuZnAl shape memory alloy
,
null
,
null
Zhongguo WEI and Dazhi YANG (Dept. of Materials Engineering
,
Dalian University of Technology
,
Dalian
,
116024
,
China)
材料科学技术（英）
The excess vacancies in ternary CuZnAl and Ti-doped CuZnAl alloys quenched from temperatures between 673 K and 1223 K, and the behaviour of the quenched-in vacancies on postquench aging in martensite phase have been studied by Doppler broadening measurements. It has been found that adding Ti to the alloys resuIts in the formation of vacancy-Ti solute atom complexes which lowers the mobility of the vacancies. In the Ti-free alloy, the prominent changes in the lineshape S-parameter during the early stage of martensite aging have evidenced the occurrence of vacancy migration to sinks, clustering or vacancy related atomic distortion. The role of the vacancies in martensite stabilization has been discussed
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