TY - JOUR
T1 - Characteristics and mechanism of martensite ageing effect in Au-Cd alloys
AU - Murakami, Y.
AU - Nakajima, Y.
AU - Otsuka, K.
AU - Ohba, T.
AU - Matsuo, R.
AU - Ohshima, K.
N1 - Funding Information:
This work was supported by the Grant-in-Aid for the General Scientific Research (Ippan B, 1995-1996) from the Ministry of Education, Science and Culture of Japan, and the Grant-in-Aid for Research Fellowship of the Japan Society for the Promotion of Science for Young Scientists (Y. Murakami, 1995). The authors are gratefnl to Prof Tetsuro Suzuki at Tsukuba Institute of Science and Technology and Prof Haydn Chert at the Univeristy of Illinois for useful discussions,
PY - 1997/9
Y1 - 1997/9
N2 - Characteristics of the martensite ageing effect was extensively studied for the ζ′2 (trigonal) martensite in Au-49.5 and 50.0at.%Cd alloys. Considerable changes in various physical properties were observed with ageing the ζ′2 martensite, such as the increase of the critical stress for the rearrangement of martensite variants and of the reverse transformation temperature etc., in addition to the appearance of the rubber-like behavior, which were shown to originate from the same origin. The ageing effect was further investigated with respect to the temperature dependence, composition dependence and the influence by heat-treatment, from which a close relation with a diffusion mechanism in the martensite was derived. The activation energy for the martensite ageing effect was determined to be 0.44 eV for the ζ′2 martensite in a furnace-cooled Au-49.5at.%Cd alloy, which was found to correspond to activation energy for migration of a vacancy in the martensite. The structural change associated with the ageing effect was examined both for the ζ′2 and γ′2 (orthorhombic) martensites in Au-Cd alloys by careful X-ray diffraction measurements. Only a small and local structural change, which was achieved by some short range diffusion, was found to be responsible for the ageing effect.
AB - Characteristics of the martensite ageing effect was extensively studied for the ζ′2 (trigonal) martensite in Au-49.5 and 50.0at.%Cd alloys. Considerable changes in various physical properties were observed with ageing the ζ′2 martensite, such as the increase of the critical stress for the rearrangement of martensite variants and of the reverse transformation temperature etc., in addition to the appearance of the rubber-like behavior, which were shown to originate from the same origin. The ageing effect was further investigated with respect to the temperature dependence, composition dependence and the influence by heat-treatment, from which a close relation with a diffusion mechanism in the martensite was derived. The activation energy for the martensite ageing effect was determined to be 0.44 eV for the ζ′2 martensite in a furnace-cooled Au-49.5at.%Cd alloy, which was found to correspond to activation energy for migration of a vacancy in the martensite. The structural change associated with the ageing effect was examined both for the ζ′2 and γ′2 (orthorhombic) martensites in Au-Cd alloys by careful X-ray diffraction measurements. Only a small and local structural change, which was achieved by some short range diffusion, was found to be responsible for the ageing effect.
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U2 - 10.1016/S0921-5093(97)00120-2
DO - 10.1016/S0921-5093(97)00120-2
M3 - Article
AN - SCOPUS:0041541757
SN - 0921-5093
VL - 237
SP - 87
EP - 101
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 1
ER -