压应力下Ti-1300合金ω相变研究

ω Phase Transformation of Ti-1300 Alloy under Compressive Stress

采用高分辨膨胀仪DIL 805 A/D研究了20 MPa压应力作用下Ti-1300合金在连续加热过程中ω相变。结果表明:20 MPa压应力抑制Ti-1300合金在连续加热时ω相变,相变开始点较无应力时有一定滞后。根据Kissinger-Akahira-Sunose模型计算得出20 MPa压应力作用下Ti-1300合金的ω相变的平均激活能为73 kJ/mol,高于无应力条件下的平均相变激活能(55 kJ/mol),亦说明压应力对合金的ω相变有一定的抑制作用,使β→ω相变更加困难。然而连续加热转变中,随ω相转变量的增加而相变激活能逐渐减小,说明压应力对ω相变的抑制作用逐渐减弱。

The ω phase transformation of Ti-1300 alloy under 20 MPa compressive stress during continuous heating was investigated using high resolution dilatometer DIL 805 A/D. Results show that the ω phase transformation of Ti-1300 alloy can be inhibited by 20 MPa compressive stress during continuous heating. The local activation energy of ω phase transformation for Ti-1300 alloy was determined on the basis of Kissinger-Akahira-Sunose（KAS） method. The average activation energy of ω phase transformation is about 73 kJ/mol under 20 MPa compressive stress, which is higher than that with no stress condition（55 kJ/mol）. However, the compress stress is able to inhibit the ω phase transformation of Ti-1300 alloy during continuous heating. Therefore, since the activation energy decreses with increase of transformed volume fraction fω, the inhibiting effect of compressive stress on ω phase transformation of Ti-1300 alloy is gradually weakened.