胡炽,刘君,刘燕红,等.Nb47Ti合金热变形行为及微观组织[J].精密成形工程,2020,12(4):132-138.
HU Chi,LIU Jun,LIU Yan-hong,et al.Hot Deformation Behavior and Microstructures of Nb47Ti Alloy[J].Journal of Netshape Forming Engineering,2020,12(4):132-138. |
| Nb47Ti合金热变形行为及微观组织 |
| Hot Deformation Behavior and Microstructures of Nb47Ti Alloy |
| 投稿时间：2020-03-23 修订日期：2020-07-10 |
| DOI：10.3969/j.issn.1674-6457.2020.04.016 |
| 中文关键词: NbTi合金 热变形 动态再结晶 微观组织 |
| 英文关键词: Nb47Ti alloy hot deformation dynamic recrystallization microstructure |
| 基金项目:国家自然科学基金（51605383）；国家重点研发计划（2017YFE0301402）；凝固技术国家重点实验室开放课题（SKLSP201641） |
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| 中文摘要: |
| 目的 研究Nb47Ti合金在变形温度为600~750 ℃、应变速率为0.001~1 s-1条件下的热变形行为和微观组织。方法 采用Gleeble-3500型热/力模拟试验机进行等温恒应变速率压缩实验，获得Nb47Ti合金热变形的真应力应变曲线，并利用EBSD技术手段分析热变形后的微观组织。结果 Nb47Ti合金在变形温度小于650 ℃、应变速率小于0.1 s-1下热变形的真应力-应变曲线为动态再结晶型曲线，变形温度大于等于700 ℃时呈现为动态回复型曲线；峰值应力随变形温度的升高和应变速率的减小而减小；在变形温度为650 ℃、应变速率为0.001 s-1下热变形组织以再结晶晶粒和亚晶粒为主，随着应变速率的增大，动态再结晶晶粒不断减少，而亚晶粒和变形晶粒增多，晶粒得到显著细化。当应变速率为0.1 s-1时，随着变形温度的增加，晶粒尺寸增大，变形温度升高至750 ℃，热变形组织中亚晶粒所占比例高达50.5%。结论 Nb47Ti合金是温度和正应变速率敏感材料，随变形温度的升高和应变速率的增大，变形过程中动态回复软化机制更为显著，低温、高应变速率下变形获得的再结晶晶粒尺寸小。 |
| 英文摘要: |
| The paper aims to research hot deformation behavior and microstructures of Nb47Ti alloy at the deformation temperatures between 600 ℃ and 750 ℃ with strain rates between 0.001 s-1 and 1s-1. The compression experiments with isothermal and constant strain rate were performed on the Gleeble-3500 thermal/mechanical simulator; and then the true stress-strain curves of the thermal deformed Nb47Ti alloy were obtained; and the microstructures after thermal deformation were also analyzed by EBSD technology. The results showed that the true stress-strain curves of the hot deformed Nb47Ti alloy were dynamic recrystallization curves when the deformation temperatures and the strain rates were less than 650 ℃ and 0.1 s-1 respectively; and were dynamic recovery curves when the deformation temperatures were more than or equal to 700 ℃. The peak stress decreased with the increase of deformation temperature and the decrease of strain rate. The microstructures deformed at the temperature of 650 ℃ with a strain rate of 0.001 s-1 were mainly composed of the recrystallized grains and sub-grains. And the dynamic recrystallization fraction continuously decreased, while the fractions of sub-grains and deformed grains increased with the increase of strain rate; at the same time, the grains were also refined significantly. However, the grain sizes increased with the increase of the deformation temperature when the strain rate was 0.1 s-1, and that the proportion of sub-grains was as high as 50.5% when the deformation temperature rose to 750 ℃. Then it can be concluded that Nb47Ti alloy is sensitive to temperature and positive strain rate. And the dynamic recovery softening mechanism becomes more significant with deformation temperature and the strain rate increasing during the deformation process; meanwhile, the dynamic recrystallization grains with a smaller size can be obtained at low temperatures and high strain rates. |
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