变形工艺参数对SP700钛合金微观组织及显微硬度的影响

Effects of Deformation Process Parameters on Microstructure and Microhardness of SP700 Titanium Alloy

采用Gleeble-3800型热模拟试验机对SP700钛合金进行等温恒应变速率压缩试验,对变形温度为700~950℃、应变速率为0.001~1 s^(-1)及最大应变量为0.9下SP700钛合金的热变形行为进行研究,并分析热变形过程中变形工艺参数对其微观组织演变及显微硬度的影响。结果表明,变形温度和应变速率对合金的峰值流动应力、微观组织演变和显微硬度都有较大的影响。当应变速率不变时,随着变形温度逐渐增大,合金的峰值流动应力降低,其微观组织中α相逐渐球化,最终发生动态再结晶,显微硬度也先增大后减小最后又增大。当变形温度不变时,随着应变速率逐渐增大,峰值流动应力增大,微观组织中α相球化率降低,且最后呈现出局部流动现象,显微硬度先增大然后减小。

The Gleeble-3800 thermal simulation testing machine was utilized to conduct isothermal constant strain rate compression experiments on SP700 titanium alloy,and the thermal deformation behavior of the alloy at deformation temperature of 700~950℃,strain rate of 0.001~1 s^(-1)and maximum strain of 0.9 was investigated.The influence law of different deformation process parameters during thermal deformation on microstructure evolution and microhardness of the alloy was analyzed.The results indicate that the deformation temperature and strain rate have a great influence on the peak flow stress,microstructure evolution and microhardness of the alloy.When the strain rate is constant,with the gradual increase of the deformation temperature,the peak flow stress of the alloy is decreased,andαphase is gradually spheroidized,which finally undergoes dynamic recrystallization,while the microhardness is increased firstly and then decreased,and finally increased again.When the deformation temperature is constant,with the gradual increase of the strain rate,the peak flow stress is increased,and the spheroidization rate ofαphase is decreased,which finally presents a local flow phenomenon,and the microhardness is firstly increased and then decreased.