热变形参数对Ti53311S合金组织的影响

Effect of hot deformation parameters on the microstructure of Ti53311S alloy

在Gleeble-1500热模拟机上对Ti53311S合金进行了变形温度为880～1080℃、变形速率为0．001—10s^-1的热压缩试验，分析了合金的热变形行为并观察了金相组织。结果表明，该合金流变应力均随应变速率的增加而升高，随温度的升高而降低。在相变点以下变形，随温度增加，合金中β相数量有所增加，但晶粒尺寸变化不大。在高温两相区980℃变形，低应变速率的组织较粗大，中等变形速率0．1s^-1可以得到晶粒细小、均匀的组织，而应变速率高于1s^-1，则会造成变形组织明显不均匀。在高温β区变形时的变形机理主要为动态回复，而且在该回复区域增加变形量并不能起到细化组织的效果。

The hot deformation test of Ti53311S alloy in the temperature range of 880 -1080 ℃and strain rate range of 0. 001 - 10 s^-1 were performed by using Gleeble-1500 simulator. The deformation behavior and microstructure were studied at different temperature. The results show that the flow stress decreases with the increase of temperature, whereas increases with the increase of strain rate. With the increase of temperature below the phase transformation temperature, the amount of β phase increases, but the grain size of β phase does not change apparently. The more coarse microstructure is obtained under low strain rate at 980℃ in the high temperature dual phase region, but the homogeneous fine grain structure is obtained at moderate strain rate. However, strain rate higher than 1 s^-1, can lead to obvious heterogeneous deformation structure. The deformation mechanism of Ti53311S alloy in β phase zone is dynamic recovery, and the grain can not be refined by increasing the deformation reduction.