Improving superficial microstructure and properties of the laser-processed ultrathin kerf in Ti-6Al-4V alloy by water-jet guiding  

作　　者：Yang Chao Yuezhuan Liu Zifa Xu Weixin Xie Li Zhang Wentai Ouyang Haichen Wu Zebin Pan Junke Jiao Shujun Li Guangyi Zhang Wenwu Zhang Liyuan Sheng 

机构地区：[1]Ningbo Institute of Materials Technology and Engineering,Key Laboratory of Aero Engine Extreme Manufacturing Technology of Zhejiang Province,CAS,Ningbo 315201,China [2]School of Mechanical Engineering,Ningbo University of Technology,Ningbo 315336,China [3]Huizhou Port Customs,Huizhou 516084,China [4]School of Mechanical Engineering,Yangzhou University,Yangzhou,Jiangsu 225127,China [5]Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [6]Shenzhen Institute,Peking University,Shenzhen 518057,China [7]PKU-HKUST ShenZhen-HongKong Institution,Shenzhen 518057,China

出　　处：《Journal of Materials Science & Technology》2023年第25期32-53,共22页材料科学技术（英文版）

基　　金：the financial support for this research by the National Key Research and Develop-ment Program of China(No.2018YFC1106702);the Natural National Science Foundation of China(NSFC)(No.51805525);the Natural Science Foundation of Zhejiang Province(Nos.LY21E050018,LY18E050027);the Innovation Guidance Foun-dation of Innovation Academy for Light-duty Gas Turbine of Chinese Academy of Sciences(No.CXYJJ20-QN-10);the Zhejiang Basic Public Welfare Research Program(No.LGG20E050009);the Ningbo 2025 Major Science and Technology Project(No.2022Z013);the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515011301,2019A1515110067,and 2020A1515110055);the Shenzhen Basic Research Project(Nos.JCYJ20210324120001003,JCYJ20200109144608205,and JCYJ20200109144604020).

摘　　要：In the present research,the gas-assisted laser(GAL)and water-jet guided laser(WGL)processing technologies were applied to machine the ultrathin kerf in the wrought Ti-6Al-4V alloy.The microstructure,microhardness,and wear properties of the superficial layer were investigated.The results reveal that the GAL processing could machine the kerf with a high depth-to-width ratio of 12–15,but the increased processing times enhance the depth little.Due to the oxygen entrainment and relatively low heat and mass transferring efficiency,the assisted gas promotes the formation of a scaled recast layer containingβ-Ti phase and oxides,which increases the roughness to 20μm.The WGL processed kerf has a low depth-to-width ratio with a value of 1.9–2.5 and the depth could be increased by increasing the WGL processing times.With the assistance of the water jet,the remelted debris and heat could be eliminated immediately,which restrains the formation of the recast layer and heat-affected zone.The ultrathin oxide outer layer with hundreds of nanometers and ultrafineα-Ti grain inner layer are formed on the surface,which decreases the roughness to 12μm.Compared with the as-received Ti-6Al-4V alloy,the microhardness of GAL processed kerf surface is increased to 382.8 HV accompanied by residual tensile stress,while the microhardness of WGL processed kerf surface is increased to 481.6 HV accompanying with residual compressive stress.In addition,the GAL processing increases the wear rate at room temperature but decreases the wear rate at high temperatures.Comparatively,the WGL processing decreases the wear rate at room and high temperatures,simultaneously.Such wear behaviors could be ascribed to their different superficial microstructures and phase constituents.

关 键 词：Ti-6Al-4V alloy Water-jet guided laser processing Superficial layer Microstructure Wear properties 

分 类 号：TB383.1[一般工业技术—材料科学与工程]