摘要
利用Gleeble1500热模拟机测试了Ti6Al4V合金在不同温度和不同应变速率下的真应力真应变曲线,观察热变形前后的组织,分析变形温度、应变速率、原始组织和热处理工艺对合金的热变形行为的作用及影响规律。结果表明,在应变速率为8.3×10-3s条件下,合金在600℃热变形时软化机制以动态回复为主,800℃至900℃热变形时软化机制以动态再结晶为主;700℃热变形时动态回复和动态再结晶可同时发生。淬火和时效可提高合金的热变形抗力。合金在600℃变形时,热变形抗力对在8.3×10-2s-8.3×100s范围变化的应变速率敏感性较差;当应变速率降至8.3×10-3s-1时,热变形抗力有较大幅度的降低。在相同的变形条件情况下,魏氏组织的流变应力高于等轴组织。
True stress-true strain curves of Ti-6Al-4V titanium alloy were measured by Gleeble-1500 Formaster Press Simulator at different temperatures and different strain rates. The microstructures of the alloy before and after deformation were observed using optical microscope. The effect of deformation temperature, strain rate, original microstructure and heat treatment processing on hot deformation behavior of Ti-6Al-4V alloy were analyzed. The results show that at 8.3 × 10-3/s strain rate, the dynamic recovery is the main softening mechanism in the alloy deformed at 600°C, and the dynamic recrystallization is the main softening mechanism in the alloy deformed at 800°C-900°C. However, the dynamic recovery and the dynamic recrystallization may occur simultaneously. The hot deformation resistance of the alloy is improved by quenching or aging, and less sensitive to the strain rate in the range of 8.3 × 10-2/s-8.3 × 100/s, but the hot deformation resistance decreases greatly at 8.3 × 10-3/s strain rate when the alloy is deformed at 600°C. The flow stress of widmanstatten structure is generally higher than that of equiaxed grain structure.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2005年第4期56-59,共4页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金资助项目(50371021)
关键词
TI-6AL-4V钛合金
热斥缩变形
显微组织
Deformation
Heat treatment
Microstructure
Recovery
Recrystallization (metallurgy)
Strain rate
Transmission electron microscopy
