(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 利用分離式Hopkinson壓桿(SHPB)技術(shù)對(duì)鈦合金TC16的帽形試樣進(jìn)行動(dòng)態(tài)加載，采用光學(xué)顯微鏡和透射電鏡技術(shù)觀測(cè)TC16中絕熱剪切帶內(nèi)的微觀結(jié)構(gòu)和相變情況。結(jié)果表明，剪切帶的邊緣由具有高位錯(cuò)密度的沿著剪切方向排列的寬度為0.2~0.5 μm的伸長(zhǎng)組織構(gòu)成，其與基體組織的形貌顯著不同；剪切帶中部由大量低位錯(cuò)密度的直徑約為0.2 μm的再結(jié)晶等軸晶組成。衍射花樣的標(biāo)定表明α-Ti和α″相共存于剪切帶中部，剪切帶內(nèi)發(fā)生了相變。絕熱剪切變形過程中剪切帶內(nèi)的溫度約為796 ℃。討論了TC16中絕熱剪切帶內(nèi)的相變規(guī)律和微觀結(jié)構(gòu)演化過程。
關(guān)鍵字: TC16合金；絕熱剪切帶；動(dòng)態(tài)再結(jié)晶；相變
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Abstract: Dynamic loading was carried out in the hat-shaped specimens of titanium alloy TC16 by split Hopkinson pressure bar (SHPB) technique. The microstructure and the phase transformation in the adiabatic shear band (ASB) produced in TC16 alloy were investigated by means of OM and TEM. The results show that the boundary of the shear band is composed of grains of 0.2−0.5 μm in width with high dislocation density elongated along the shear direction, whose pattern is obvious different from the matrix grains. The center of shear band consists of a number of recrystallized equiaxed grains with diameters of about 0.2 μm with low dislocation density. The results of SAD indicate that α-Ti and α″ grains coexist in the shear band and the phase transformation occurs in the shear band. The temperature in the shear band during the adiabatic shearing deformation is about 796 ℃. The phase transformation and the microstructure evolution process within ASB in TC16 alloy were explained.
Key words: TC16 alloy; adiabatic shear band; dynamic recrystallization; phase transformation
