锻压技术

基于热加工图的Ti-46.5Al-2.5V-1.0Cr-0.3Ni合金高温变形特性研究

英文标题：Hot deformation characteristics of Ti-46.5Al-2.5V-1.0Cr-0.3Ni alloy using processing maps

作者：司家勇高帆张继

分类号：TG146.2

出版年,卷(期):页码：2010,35(6):112-118

摘要：

在Gleeble-1500热模拟机上对Ti-46.5Al-2.5V-1.0Cr-0.3Ni合金进行了热压缩实验，采用动态材料模型的加工图研究了其在1000～1200 ℃和0.001～1.0 s^-1条件下的热变形行为。结果表明，Ti-46.5Al-2.5V-1.0Cr-0.3Ni合金在热变形时呈现两个微观机制不同的动态再结晶峰区，其中动态再结晶区域Ι区：峰值效率为34％，峰值对应的温度和应变速率分别为1100 ℃和0.01 s^-1；动态再结晶区域ΙΙ区：峰值效率为34％，峰值对应的温度和应变速率分别为1105 ℃和0.001 s^-1。在温度低于1140 ℃、应变速率大于0.01 s^-1范围内进行热加工时，由于热塑性变形过程中再结晶晶粒的不均匀长大，极易导致试样变形开裂。在温度1000～1130 ℃，变形速率大于0.02 s^-1区域内，热压缩变形试样外表面剪切开裂趋势明显，易引起加工失稳。根据热加工图分析结果可知，TiAl合金热变形时应选择在动态再结晶Ι区内进行。

The hot deformation behaviors of Ti-46.5Al-2.5V-1.0Cr-0.3Ni alloy in the temperature range of 1000-1200 ℃ and strain rate range of 0.001-1.0 s^-1were studied using hot compressing testing on a Gleeble\|1500 simulator. And a processing map was developed on the basis of these data and the principles of dynamic material modeling. The map exhibits two domains: the first one at 1100 ℃ and 0.01 s^-1 with a peak efficiency of power dissipation of 34%, the second one at 1105 ℃ and 0.001 s^-1 with a peak efficiency of power dissipation of 34%. Optical microscopic observations show that they represent two dynamic recrystallization (DRX) domains with different mechanisms. At temperatures lower than 1140 ℃ and strain rates higher than 0.01 s^-1, the material may be subjected to potential instabilities for the inhomogeneous growing of dynamic recrystallization grains during the hot deformation. At temperatures 1000-1130 ℃ and strain rates higher than 0.02 s^-1, the shear crack of the samples is obviously. On the basis of the above processing map, the hot deformation should be carried out in the dynamic recrystallization domains Ι.

基金项目：

863国家高技术研究发展计划(2006AA03A204)

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