(1. 中國石油大學(xué)(華東) 機電工程學(xué)院，青島 266580；
2. 浙江大學(xué) 舟山海洋研究中心，舟山 316021)
摘 要: 為了提高TA2 鈦合金的耐磨性和耐蝕性，采用激光相變硬化-氣體滲氮工藝對TA2 鈦進行表面改性。利用體視光學(xué)顯微鏡、透射電鏡和X 射線衍射儀對TA2 激光相變硬化-氣體滲氮層進行表面形貌、微觀組織和相組成分析；利用顯微硬度計對兩種復(fù)合改性層的顯微硬度進行測試。結(jié)果表明：TA2 鈦表面經(jīng)激光相變硬化后，可實現(xiàn)430 ℃低溫滲氮。此條件下晶粒得到細化，亞結(jié)構(gòu)和缺陷密度的增加有利于氮元素和晶內(nèi)擴散，相變組織與氮勢梯度具有良好的對應(yīng)關(guān)系。通過改善滲層的組織結(jié)構(gòu)和化學(xué)成分分布狀態(tài)，獲得了性能優(yōu)良的TA2 鈦表面硬化層。
關(guān)鍵字: TA2 鈦；激光相變硬化；低溫滲氮；機理
（1. College of Electrical and Mechanical Engineering,China University of Petroleum,Qingdao 266580,China
2. Ocean Research Center of Zhoushan,Zhejiang University,Zhoushan 316021,China）
Abstract:To improve the abrasion resistance and corrosion resistance of TA2 titanium,a laser transformation hardening-gas nitriding process was adopted to carry out the surface modification. Analysis was made for the surface morphology,microstructure and phase constitution of TA2 laser transformation hardening-gas nitrided layer by OM,TEM and XRD; and microhardness tester was used to test the microhardness of the two composite modified surfaces. The results indicate that after undergoing laser transformation hardening,the surface of TA2 titanium can be nitrided at a low temperature of 430 ℃. Under this condition,the grains are refined. The increase in sub-structure and defect density is more conducive to the intragranular diffusion of nitrogen,and there is a good correspondence between the phase transformation structure and nitrogen potential gradient. TA2 titanium surface-hardened layer with good performance is obtained through improving the structure of nitrided layer and the distribution of its chemical components.
Key words: TA2 titanium; laser transformation hardening; low-temperature nitriding; mechanism
