Transmission electron microscopy of twins in martensite in Ti-Pd shape memory alloy

Journal Article · Sat Nov 01 00:00:00 EST 1997 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00162-6· OSTI ID:590036

Nishida, M; Morizono, Y; Ikeya, A; Kijima, H; Chiba, A ^[1]; Hara, T ^[2]

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1. Kumamoto Univ., Kurokami, Kumamoto (Japan). Dept. of Materials Science and Engineering
2. 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, Vol. 45, Issue 11; Other Information: PBD: Nov 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TITANIUM ALLOYS
PALLADIUM ALLOYS
TWINNING
SHAPE MEMORY EFFECT
MORPHOLOGY
CRYSTALLOGRAPHY