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采用快速凝固法制备了Ti53.5Ni22.8Cu23.7合金薄带。用透射电镜(TEM)、电子探针(EPMA)和电子拉伸试验机对铸态和退火态下的条带进行力学分析、组织分析及断口形貌分析。研究发现,铸态下Ti53.5Ni22.8Cu23.7合金条带的抗拉强度和断裂应变分别为1257MPa和3.86%。其断口形貌有明显的脉状条纹和光滑非晶无特征区。条带经450℃退火10min和60min后其断裂强度分别为623MPa和850MPa,条带的弹性模量随着应变增加从7~10GPa增至25GPa。退火后条带拉伸断口均体现出等轴晶粒形貌。经450℃,60min退火的合金条带拉伸前后的TEM形貌特征不同,拉伸后的奥氏体晶粒中局部出现应力,诱发马氏体相变,从而形成马氏体板条。
Ti53.5Ni22.8Cu23.7 alloy ribbons were prepared by rapid solidification. The mechanical analysis, microstructure analysis and fracture surface morphology of the as-cast and annealed ribbons were carried out by TEM, EPMA and electronic tensile testing machine. The results show that the tensile strength and fracture strain of Ti53.5Ni22.8Cu23.7 alloy are 1257MPa and 3.86%, respectively. The fracture morphology has obvious veins stripes and smooth amorphous non-characteristic area. The rupture strength of the tape after annealed at 450 ℃ for 10min and 60min were 623MPa and 850MPa, respectively. The elastic modulus of tape increased from 7 ~ 10GPa to 25GPa with the increase of strain. The annealed strip tensile fracture shows the equiaxed grain morphology. After being annealed at 450 ℃ for 60 min, the TEM features of the alloy strips before and after stretching are different. Local stress in the austenite grains after stretching causes martensite transformation to form martensite laths.