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本文研究了扭转条件下TC4(Ti—6Al—4V)在不同温度(800～920℃)、等效变形速度(9.13×10~(-4)～3.40×10~(-2)S~(-1))下的超塑特征。结果表明:扭矩随应变速度增加而增加,随温度增加而减少。同一温度下,存在一最佳变形速率γ,此时可获最大塑性指标ε_(max)。挤压状态试件在850℃时,最佳变形速度为8.747×10~(-3)S~(-1),此时ε_(max)高达1988%,m值大于0.31,变形后组织变为明显等轴晶。通常γ>10~(-2)S~(-1)时,超塑指标明显降低。推证了m值计算公式,测定了m值,所作1gM/1gγ保持直线关系。分析了扭转塑性指标的确定原则及各种影响因素。
In this paper, the effects of TC4 (Ti-6Al-4V) under different temperatures (800-920 ℃) and equivalent deformation velocities (9.13 × 10-4 ~ 3.40 × 10 -2) S ~ (- 1)) under the super-plastic features. The results show that torque increases with increasing strain rate and decreases with increasing temperature. At the same temperature, there is an optimum deformation rate γ, at which point the maximum plasticity ε max can be obtained. At 850 ℃, the optimum deformation rate is 8.747 × 10 -3 S -1, and the maximum value of ε max is about 1988%. The value of m is greater than 0.31. After deformation, the microstructure becomes Obviously equiaxed. Usually γ> 10 ~ (-2) S ~ (-1), the superplastic index decreased significantly. The calculation formula of m was deduced, the value of m was determined, and the relation of 1gM / 1gγ was kept in a straight line. The principle of determination of torsional plastic index and various influencing factors are analyzed.