(1. 北京航空制造工程研究所，北京 100024；
2. 大連理工大學(xué) 材料科學(xué)與工程學(xué)院，大連 116085；
3.南京航空航天大學(xué) 機電學(xué)院，南京 210016)
摘 要: 利用金相顯微鏡、X射線衍射儀和掃描電鏡對置氫Ti-6Al-4V合金的微觀組織和相組成及切屑形貌進行了觀察分析，采用分離式Hopkinson壓桿試驗測試置氫Ti-6Al-4V合金的動態(tài)力學(xué)性能，研究氫對Ti-6Al-4V切屑形成過程及切屑形態(tài)的影響，探討置氫Ti-6Al-4V合金的切屑形成機制。結(jié)果表明：置氫后Ti-6Al-4V合金切屑的收縮系數(shù)增加，表面層片結(jié)構(gòu)尺寸減小，切屑鋸齒化程度減輕；氫含量低于0.4%(質(zhì)量分數(shù))時，局部材料熱塑失穩(wěn)是形成鋸齒切屑的主要原因，隨氫含量增加，鈦合金切屑的絕熱剪切現(xiàn)象減輕，隨著氫含量的進一步增加，鋸齒切屑的形成是由微裂紋而致。
關(guān)鍵字: Ti-6Al-4V合金；置氫；切屑形成；絕熱剪切
cutting hydrogenated Ti-6Al-4V alloys
（1. Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024, China;
2. School of Material Sciences and Engineering, Dalian University of Technology, Dalian 116085, China;
3. School of Mecharonics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China）
Abstract:The microstructure and phase composition of hydrogenated Ti-6Al-4V alloys and the morphology of chip were observed optical microscopy, X-ray diffractometry and scanning electron microscopy. The split Hopkinson bar was employed to test the dynamic mechanical property. The morphology and mechanism of chip formation in cutting Ti-6Al-4V alloys were investigated. The results show: compared with unhydrogenated chip, the chip compression ratio of hydrogenated Ti-6Al-4V alloys is greater, the dimension of lamellae and saw-tooth are less significantly. The thermo-plastic instability is the mechanism of saw-tooth chips formation due to the large plastic deformation when the addition o hydrogen is less than 0.4% (mass fraction). In contrast, the crack initiation mechanism is responsible for the saw-tooth chip with more hydrogen content.
Key words: Ti-6Al-4V alloy; hydrogen treatment; chip formation; adiabatic shearing
