冷轧变形量及退火温度对Ti-7.5Nb-4Mo-2Sn合金织构和超弹性的影响

Effects of cold rolling deformation and annealing temperature on texture and superelasticity of Ti-7.5Nb-4Mo-2Sn alloy

研究冷轧变形量（40%、75%和95%）和退火温度（650、750和850℃）对亚稳β钛合金Ti-7.5Nb-4Mo-2Sn（原子分数,%）的显微组织、织构和超弹性的影响。结果表明：不同冷轧变形量变形后,合金中出现了{111}〈110〉,{111}〈112〉和{001}〈110〉型冷轧织构,随变形量增大,冷轧织构强度有小幅度增加,其中以{111}〈112〉、{111}〈110〉型织构强度增幅度最大;经过650~850℃退火后,合金发生再结晶,并形成了再结晶织构,其中变形量为95%、650℃退火后,试样的组织由细小的等轴状β相构成,同时形成了较强的{112}〈110〉,{111}〈112〉再结晶织构,合金试样表现出较好的超弹性,其应变回复率71.5%;细小的等轴晶组织和{111}〈112〉再结晶织构,能提高合金的超弹性能。

The effects of cold rolling deformation（ 40%,75% and 95%） and annealing temperature（ 650,750 and 850 ℃） on microstructure,texture and superelasticity of a metastable β titanium alloy Ti-7. 5 Nb-4 Mo-2 Sn（ atomic fraction,%） were investigated.The results show that after cold rolling with different rolling reductions,the cold rolling texture of { 111} 110 ,{ 111 } 112 and{ 001} 110 appears in the alloy; with the increasing of rolling deformation,the intensity of the cold rolling texture increases slightly,and the increasing amount of intensity of the { 111} 112 and { 111} 110 texture is the greatest. After annealing at the temperature of 650-850 ℃,recrystallization occurs in the cold rolled alloy and the recrystallization texture is formed. The microstructure of the alloy with the cold rolled reduction of 95% is composed of fine equiaxed β grains after annealing at 650 ℃,and the relatively strong { 112 } 110 and { 111} 112 recrystallization texture is formed. The alloy exhibits good superelasticity,and the strain recovery rate is71. 5%. The fine equiaxed structure and the { 111} 112 recrystallization texture can improve the superelasticity of the alloy.