|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advances in Titanium Technology
||Microstructure, Transformation Behavior and Superlasticity of an Aged Ti-40Ni-12Cu (at. %) Shape Memory Alloy
||Jin-hwan Lim, Ji-hyun Kim, Jung-gi Kim, Tae-kyung Lee, Shuanglei Li, Tae-hyun Nam
|On-Site Speaker (Planned)
Aging behavior and mechanical properties of a (Ni,Cu)-rich Ti-40Ni-12Cu shape memory alloy were investigated. Ti(Ni,Cu)2 phase formed during solidification remained after solution treatment at 1123 K and was almost dissolved into matrix after 1373 K solution treatment. Aging at 723 K increased hardness of the 1373 K solution treated specimen, which was ascribed to the formation of C11b-type precipitate that has tetragonality of 1.05 and coherent interface with matrix. Transformation temperatures of aged specimens were dependent on aging time, which were explained by composition, strain field around the precipitates and mean free path between precipitates. Aging at 873 K for 45 h of the 1373 K solution treated specimen induced the precipitation of stable Ti(Ni,Cu)2 phase, thus C11b-type precipitate was considered to be transient metastable precipitate. The specimen aged at 723 K for 2.5 h showed excellent superelasticity, which was ascribed to precipitation hardening due to metastable C11b-type precipitates.
||Titanium, Phase Transformations,