Severe plastic deformation of Ti74Nb26 shape memory alloys

Ma, J.; Karaman, I.; KOÇKAR, BENAT; Maier, H.; Chumlyakov, Y.

doi:10.1016/j.msea.2011.06.051

Severe plastic deformation of Ti74Nb26 shape memory alloys

Ma J., Karaman I., KOÇKAR B., Maier H. J., Chumlyakov Y. I.

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, cilt.528, ss.7628-7635, 2011 (SCI-Expanded)

Yayın Türü: Makale / Tam Makale
Cilt numarası: 528
Basım Tarihi: 2011
Doi Numarası: 10.1016/j.msea.2011.06.051
Dergi Adı: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Sayfa Sayıları: ss.7628-7635
Hacettepe Üniversitesi Adresli: Evet

Özet

Severe plastic deformation of Ti74Nb26 shape memory alloy was conducted successfully at room temperature using equal channel angular extrusion (ECAE). In conjunction with short post-extrusion heat treatments. ECAE improved the maximum transformation strain of the alloy from 1% to 1.7%. Moreover, it drastically reduced the irrecoverable strain during constant-stress thermal cycling experiments. After identical heat treatments, the specimens processed by one pass ECAE possess both higher transformation strain and higher irrecoverable strain as compared to those processed by four pass ECAE. However, the difference between the crystallographic texture contributions to the transformation strains of these specimens was minimal, and thus, the shape memory characteristics are believed to be influenced mainly by microstructural features. High dislocation density, small grain size, and precipitation of the omega phase were found to reduce not only the irrecoverable strain, but also the transformation strain. (C) 2011 Elsevier B.V. All rights reserved.