退火工艺对Ti-50.8Ni形状记忆合金相变和低温形变特性的影响
Effect of Annealing Process on Transformation and Deformation Characteristics of Ti-50.8Ni Shape Memory Alloy at Low-temperature
刘 艳1, 贺志荣1, 王 芳2, 杨 军1
点击：3283次 下载：0次
作者单位：1. 陕西理工学院 材料科学与工程学院, 陕西 汉中 723003; 2. 陕西理工学院 图书馆, 陕西 汉中 723003
中文关键字：Ti-50.8Ni合金； 形状记忆合金； 退火； 相变； 低温形变
英文关键字：Ti-50.8Ni alloy; shape memory alloy; annealing; transformation; low-temperature deformation
中文摘要：用示差扫描量热仪和拉伸试验研究了退火温度Tan和退火时间tan对Ti-50.8Ni形状记忆合金相变和低温形变特性的影响。Tan=350～800 ℃时，随Tan升高，合金冷却/加热相变类型发生由A?邛R?邛M/M?邛R?邛A型向A?邛R?邛M/ M?邛A型再向A?邛R/R?邛A型转变(A-母相，R-R相，M-马氏体)，且R相变温度TR先升高后降低， M相变温度TM升高，M相变热滞ΔTM降低，R相变热滞ΔTR(约4 ℃)基本不变。随tan延长，400 ℃退火态合金的相变类型A?邛R?邛M/M?邛R?邛A保持不变，500 ℃退火态合金的相变类型发生由A?邛R?邛M/M?邛R?邛A型向A?邛R?邛M/M?邛A型转变，且TM升高，ΔTM降低，TR和ΔTR不变。600～700 ℃退火态合金的塑性显著大于350～550 ℃退火态合金。在12 ℃变形时，600 ℃以上温度退火态合金呈现SE特性，600 ℃以下温度退火态合金呈现SME特性。随tan延长，合金应力-应变曲线上的平台应力降低。要使Ti-50.8Ni SMA在较低温度下获得SE，退火温度应在600 ℃以上。
英文摘要：The effects of annealing temperature (Tan) and annealing time (tan) on the transformation and deformation characteristics at low-temperature of Ti-50.8Ni shape memory alloy were investigated by DSC and tensile test. As Tan=350～800 ℃, with the increase of Tan, the transformation types of the alloy change from A?邛R?邛M/M?邛R?邛A to A?邛R?邛M/M?邛A to A?邛R/R?邛A (A-parent phase, R-R phase, M-martensite), and the R transformation temperature (TR) increases first and then decreases, the M transformation temperature (TM) increases, the M temperature hysteresis (ΔTM) decreases, the R temperature hysteresis (ΔTR) (about 4 ℃) nearly does not change. With the increase of tan, the transformation types of the alloy annealed at 400 ℃ keep as A?邛R?邛M/M?邛R?邛A, while change from A?邛R?邛M/M?邛R?邛A to A?邛R?邛M/M?邛A at 500 ℃, and the TM increases, the ΔTM decreases, the TR and ΔTR are nearly constant. The ductility of the alloy annealed at 600～700 ℃ is significantly greater than that at 350～550 ℃. When deforms at 12 ℃, the alloys annealed at above 600 ℃ show SE, the alloys annealed at below 600 ℃ show SME. With the increase of tan, the platform stress in the stress-strain curves decreases. To obtain SE for Ti-50.8Ni SMA at low-temperature, the annealing temperature should be above 600 ℃.