近α钛基复合材料β相区间热压缩变形行为

A Study on the Thermal Compression Deformation Behavior of Near-α Titanium Matrix Composites in β Phase

利用Gleeble3800热力模拟试验机对网状结构近α钛基复合材料进行真应变为0.8、温度为1080℃和1200℃、应变速率为0.001~1 s^(-1)条件下的热压缩实验.应力应变曲线表明:高应变速率下,应力达到峰值后迅速降低,表现出明显的动态再结晶(DRX)特征;低应变速率下,应力达到峰值后随应变量的增加基本保持不变,表现出明显的动态回复(DRV)特征.通过金相、SEM和EBSD观察分析材料的微观组织演变规律.金相分析结果表明:网状结构的变形程度与所处区域有关,中间区域变形最为严重,网状结构被严重压扁.SEM分析结果表明:低应变速率下,增强体破碎程度较弱,且保存有少量完整的增强体晶须;高应变速率下,增强体破碎严重,少量增强体发生严重破损.EBSD分析结果表明:高应变率下,变形机理主要是DRX;低应变率下,变形机理主要是DRV.

The Gleeble 3800 thermal simulation test machine was used to perform thermal compression experiments on network structure near-αtitanium composite material with true strain of 0.8,temperatures of 1080°C and 1200°C,and strain rates of 0.001-1 s^(-1).The stress-strain curve showed that at high strain rates,the stress rapidly decreased after reaching the peak value,indicating obvious DRX characteristics;at low strain rates,the stress was basically unchanged after reaching the peak value,indicating obvious DRV characteristics.The metallurgical,SEM and EBSD observations were used to analyze the microstructure evolution of the material.The results of metallographic analysis showed that the degree of deformation of the network structure was related to the area in which it was located.The deformation in the middle area was the most serious,and the mesh structure was severely squashed.SEM results show that at low strain rates,the reinforcement was weakly broken,and a small number of complete reinforcement whiskers are kept;at high strain rates,the reinforcement was severely broken,and a small number of reinforcements are severely damaged.The results of EBSD analysis showed that at high strain rate,the deformation mechanism was mainly DRX;at low strain rate,the deformation mechanism was mainly DRV.