TC4表面脉冲等离子填丝-送粉熔覆WC/Ti组织及强韧性研究

Microstructure and Strength-Toughness of Pulsed Plasma Filamentpowder Feeding Cladding WC/Ti Layer on TC4

为提升全钛部件表面耐磨及耐冲击性能,以WC颗粒和TC4焊丝作为熔覆材料,采用脉冲等离子填丝-送粉熔覆技术在TC4钛合金表面制备WC/Ti复合层。通过试验获得其中最优WC/Ti的比例,并研究其对熔覆层硬度及强韧性的影响,分析了WC/Ti熔覆层金相组织形貌、显微硬度、冲击韧性、熔覆层与基材结合强度。试验结果表明,通过优化工艺参数,获得表面呈现亮黑色、内部无冶金缺陷的WC/Ti熔覆层,熔覆层主要由WC、TiC、W2C等相组成,在WC颗粒周围产生了以TiC相为主的强化组织。当送丝速率为1.4 m/min,送粉速率为18 g/min时,熔覆层表面硬度达到51.9 HRC,是TC4基材的1.5倍以上。冲击韧性测试结果表明,熔覆层在室温下具有一定的抗冲击性能,侧向冲击吸收功平均值为10.6 J。熔覆层与基材的结合强度达到616.03 MPa,远超工程指标450 MPa。脉冲等离子熔覆技术可以有效制备WC/Ti复合层,提升TC4钛合金表面的耐磨性和冲击韧性。

To enhance the wear and impact resistance of titanium components,WC particles and TC4 welding wire were used as cladding materials.Pulse plasma wire-powder cladding technology was employed to prepare a WC/Ti composite layer on the surface of TC4 titanium alloy.The optimal ratio of WC/Ti was determined through experiments,and its effects on the hardness and toughness of the cladding layer were studied.The microstructure,microhardness,impact toughness,and bonding strength between the cladding layer and substrate were analyzed.The results showed that by optimizing process parameters,a WC/Ti cladding layer with a bright black surface and no metallurgical defects inside was obtained.The cladding layer mainly consists of phases such as WC,TiC,W2C,etc.,with a strengthened structure primarily composed of TiC phase around the WC particles.When the wire feed rate is 1.4 m/min and the powder feed rate is 18 g/min,the surface hardness of the cladding layer reaches 51.9 HRC,which is more than 1.5 times that of the TC4 substrate.The impact toughness test results indicate that the cladding layer has certain impact resistance at room temperature,with an average lateral impact absorption work of 10.6 J.The bonding strength between the cladding layer and the substrate reaches 616.03 MPa,far exceeding the engineering index of 450 MPa.Pulse plasma cladding technology can effectively prepare WC/Ti composite layers,enhancing the wear and impact resistance of TC4 titanium alloy surfaces.