(西安建筑科技大學(xué) 冶金工程學(xué)院，西安 710055)
摘 要: 研究連續(xù)變斷面循環(huán)擠壓變形道次、變形溫度、變形速度對(duì)TC4合金組織的影響。結(jié)果表明：在臨近再結(jié)晶溫度變形時(shí)，隨著變形道次的增加，晶粒的細(xì)化程度隨之增加；而在較高溫度變形時(shí)，隨著變形道次的增加，晶粒的細(xì)化程度先增大后減小，且6道次的細(xì)化效果較佳。隨著變形溫度的升高，由于再結(jié)晶的作用，晶粒的細(xì)化程度先增大再減小，且在800 ℃變形時(shí)，細(xì)化效果較佳；提高變形速度有利于晶粒的細(xì)化，但當(dāng)變形速度過高時(shí)，組織分布的均勻性較差。當(dāng)TC4合金在800 ℃以2 mm/s經(jīng)6道次變形后，初生α相尺寸由14 μm細(xì)化至2~ 3 μm左右，且組織分布較均勻。
關(guān)鍵字: TC4合金；連續(xù)變斷面循環(huán)擠壓；顯微組織；晶粒細(xì)化
（School of Metallurgical Engineering, Xi’an University of Architecture & Technology, Xi’an 710055, China）
Abstract:The TC4 titanium alloy was deformed by continuous variable cross-section recycling extrusion (CVCE), and the effects of deformation loop, temperature and speed on the microstructure were investigated. The results show that, near the recrystallization temperature, the grain size of the alloy decreases rapidly with increasing deformation loop. However, when deformed at higher temperature, the refinement degree of the grain increases firstly, and then decreases with the increase of deformation loops, and the refinement effect of 6 loops is better. Moreover, with the increase of deformation temperature, the grain size decreases firstly, and then increases due to recrystallization, and the refinement effect is better as the specimen is deformed at 800 ℃. The higher deformation speed is beneficial to refine the grain, but too high deformation speed is unfavourable for the distribution uniformity of microstructure. When the specimen is deformed at 800 ℃ and 2 mm/s for 6 loops, the size of the primary α phase reduces from 14 μm to 2-3 μm, and the microstructure distributes homogeneously.
Key words: TC4 alloy; continuous variable cross-section recycling extrusion; microstructure; grain refinement
