重离子辐照诱发TiNiCu合金非晶化的原位电子显微研究

Ion irradiation-induced amor phizat ion of TiNiCu shape memory alloy

在美国Argonne国家实验室连接有IVEM-Tandem National Facility加速器的Hi-tatch3000电子显微镜上,通过400KeV Xe^+离子就位辐照研究了TiNiCu形状记忆合金的常温晶态-非晶态转变。入射的Xe离子通过级联碰撞,从0.05 dpa开始辐照诱发TiNiCu合金化学无序,非晶化过程和化学无序几乎同时进行;0.2dpa后,马氏体变体的衬度明显减小,变得非常模糊;在0.4dpa非晶化转变完成,马氏体变体的衬度完全消失。

The 400 keV Xe+ ion irradiation and in-situ TEM observation were performed in a TiNiCu shape memory alloy using the HVEM-Tandem Facility at the Argonne National Laboratory at the room temperature, and the ion flux was 1.25×1011 ions/cm2 s. The structural damage upon irradiation was monitored by the selected area electron diffraction patterns (SAED) under in-situ TEM observations. The amorphization trasformation was determined by the disappearance of all diffraction maxima in the SAED patterns and microstructural contrast. The results show that the disorder starts at 0.05 dpa, and the contrast of martensitic variants and the superlattice start disappearing in the TiNiCu shape.sample. The TiNiCu shape memory alloy becomes amorphous at a dose of -0.4 dpa.