TC4钛合金高温本构关系的研究

Study on Constitutive Relationship for Hot Deformation of TC4 Alloy

在Gleeble-1500热模拟机上对TC4钛合金进行高温热压缩试验,热模拟压缩试验变形条件:温度800～1030℃,应变速率0.001～10 s-1;变形程度60%。结果表明:TC4钛合金在变形开始阶段,流动应力随应变的增加迅速增加,当应变超过一定值后,流动应力开始下降并逐渐趋于稳定,出现稳态流动特征;变形温度、应变速率的减小使TC4钛合金高温变形时的峰值应力显著降低。并通过对数据的回归处理,确定了合金在(α+β)相区地热变形激活能是565.96 kJ/mol,β相区是402.879 kJ/mol。研究发现峰值应力σp、稳态应力σres、峰值应变εp、稳态应变εres等与Z参数之间呈线性关系。

The hot compression deformation of TC4 alloy was carried out on Gleeble-1500 hot simulator at 800-1030 ℃, and the strain rate of 0.001-10 s-1 and the plastic deformation degree of 60%.The results show that the flow stress of TC4 alloy increases quickly with the strain increasing and reaches a peak, then decreases to a steady value. The steady and peak stress significantly decrease with the increase of deformation temperature and decrease of strain rate. Using the linear method, the activation energy in （α＋β） phase area is 565.96 kJ/mol and 402.879 kJ/mol in 13 phase area. The good linear relationship was discovered between peak stress , steady stress peak strain , steady strain and Z parameter.