Transmission electron microscopy of twins in martensite in Ti-Pd shape memory alloy
- Kumamoto Univ., Kurokami, Kumamoto (Japan). Dept. of Materials Science and Engineering
- Teikyo Univ., Toyosatodai, Utsunomiya (Japan). Dept. of Materials Science and Engineering
Twins in the B19 martensite in the Ti-Pd shape memory alloy have been investigated by conventional transmission electron microscopy (CTEM) and electron diffraction. There were three twinning modes, i.e. {l_brace}111{r_brace} Type I, <121> Type II and {l_brace}101{r_brace} compound twins, in the martensite. The {l_brace}111{r_brace} Type I and <121> Type II twinnings which were conjugate to each other coexisted in a same martensite variant. The {l_brace}111{r_brace} Type I twins were dominantly observed and the <121> Type II twins were less frequently observed. The former twinning was considered to be a lattice invariant shear. The Type II twin plate appeared in two types of forms. The first one was directly connected to the Type I plate. In other words, the twin plate was inclined at crystallographically defined angle. The second one branched off from the Type I plate. Since there was no martensite variant consisting wholly of the <121> Type II twins throughout the present observations, the <121> Type II twins were considered to be a deformation twin due to the elastic interaction during the transformation. The {l_brace}101{r_brace} compound twinning was also considered to be a deformation twin which was introduced as a result of elastic interactions during the transformation since the twin had an isolated fashion in the martensite variant consisting of {l_brace}111{r_brace} Type I twins.
- OSTI ID:
- 590036
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 11 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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