激光选区熔化制备TiC强化M2高速钢组织与性能  

Selecting laser melting to prepare TiC-strengthened M2 high-speed steel for microstructure and properties

作　　者：刘岩 赵定国 李月 王书桓 崔小杰 吴朋越 苏新磊 LIU Yan;ZHAO Dingguo;LI Yue;WANG Shuhuan;CUI Xiaojie;WU Pengyue;SU Xinlei(College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,Hebei,China;Beijing E-plus 3D Technology Co.,Ltd.,Beijing 102206,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210 [2]北京易加三维科技有限公司,北京102206

出　　处：《钢铁》2024年第6期104-111,134,共9页Iron and Steel

基　　金：中央引导地方科技发展资金资助项目(226Z1008G);国家自然科学基金资助项目(52274336)。

摘　　要：M2高速钢(high-speed steel,HSS)作为一种中合金高碳工具钢,广泛应用于机加工行业中。使用激光选区熔化技术可以直接制备出具有精细复杂结构的工件,研究了TiC强化的M2高速钢的SLM成型工艺参数,分析了TiC的添加对M2高速钢微观组织、物相、性能的影响。试验结果表明,当激光功率为270 W、扫描速度为700 mm/s、扫描间隔为100μm时可以制备出相对致密度为97%以上的TiC强化M2高速钢样品。金相分析结果表明,打印态M2高速钢XZ面微熔池内部以柱状晶组织为主,而添加质量分数为1%的TiC后,XZ面柱状晶组织则全部变成等轴晶组织;SEM结果显示XY面组织以等轴晶为主,并且分布较为均匀,晶粒边界处存在点状析出物,TEM结果显示析出物主要为添加的纳米TiC粒子及析出的碳化物。添加TiC后样品的平均晶粒尺寸由1.440μm变为0.585μm,晶粒细化效果明显。XRD结果显示纯M2高速钢的物相主要为BCC马氏体,含有少量的FCC残余奥氏体。随着TiC的加入,XRD衍射峰中MxCy型碳化物的峰强度增加,TiC的加入诱导了碳化物的生成,添加质量分数为1%TiC的M2高速钢的耐磨性较纯M2高速钢提升约39%,TiC的加入起到了晶粒细化和析出强化作用,细小的晶粒及析出的碳化物显著地提升了高速钢耐磨性。M2 high-speed stee(l HSS),a medium-alloyed,high-carbon tool steel,is widely used in the machining industry.The use of selective laser melting(SLM)technology enables the direct fabrication of components with fine and complex structures.The SLM process parameters for TiC-reinforced M2 high-speed steel,analyzing the influence of TiC addition on the steel′s microstructure,phase composition,and properties were investigated.Experimental findings demonstrate that TiC-reinforced M2 high-speed steel samples with a relative density exceeding 97%can be prepared using a laser power of 270 W,scanning speed of 700 mm/s,and hatch spacing of 100μm.Metallographic analysis reveals that the as-printed M2 high-speed steel primarily exhibits a columnar crystal structure on the XZ plane,which completely transitions to an equiaxed structure upon the addition of 1%TiC.SEM results show that the XY plane structure is predominantly equiaxed,with a uniform distribution and dot-like precipitates present at grain boundaries.TEM analysis indicates these precipitates are mainly the added nano-TiC particles and other carbides.The average grain size in the TiC-added samples decreased from 1.440μm to 0.585μm,evidencing significant grain refinement.XRD results indicate that the phase of pure M2 high-speed steel is primarily BCC martensite with a minor amount of residual FCC austenite.The addition of TiC leads to an increase in the peak intensity of MxCy-type carbides in the XRD diffraction patterns,indicating that TiC addition promotes carbide formation.The wear resistance of M2 high-speed steel with 1%TiC is enhanced by about 39%compared to pure M2 high-speed steel,attributable to the grain refinement and precipitation strengthening effects of TiC.The fine grains and precipitated carbides significantly improve the wear resistance of the high-speed steel.

关 键 词：M2高速钢 激光选区熔化 摩擦磨损 TIC 碳化物 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]