Ti、Al元素对FeCoCrNiCu_(0.3)高熵合金涂层微观组织与耐磨性的影响

Effects of Ti and Al Elements on Microstructure and Wear Resistance of FeCoCrNiCu_(0.3) High Entropy Alloy Coating

采用了激光熔覆同步送粉技术在38CrMoAl表面制备了FeCoCrNiCu_(0.3)、FeCoCrNiTiCu_(0.3)与FeCoCrNiAlCu_(0.3)高熵合金涂层,采用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱分析仪(EDS)、维氏硬度计和摩擦磨损试验机等分别对高熵合金涂层的物相、微观组织与耐磨损性能进行了系统的表征。结果表明:Ti、Al元素的添加促进了涂层相结构由面心立方结构(FCC)向体心立方结构(BCC)转变,变为BBC+FCC相,Al元素对促进高熵合金中BCC相的形成更有效果,使BCC相成为了合金的主导相。Ti、Al元素的加入使得熔覆区的枝晶组织更为细化并且枝晶间距减小。FeCoCrNiAlCu_(0.3)具有更高的显微硬度,最高为683.5 HV_(0.3)。Ti、Al元素对高熵合金涂层耐磨性的影响与硬度趋势相似,FeCoCrNiAlCu_(0.3)表现出了更好的耐磨性,涂层的磨损机理随着Al元素的添加由疲劳磨损转变为磨粒磨损,Ti元素的加入使得涂层的磨损机理完全转变为疲劳磨损,Ti、Al元素对促进磨损机理的转变出现了相反的趋势。

FeCoCrNiCu_(0.3),FeCoCrNiTiCu_(0.3)and FeCoCrNiAlCu_(0.3)high entropy alloy coatings were prepared on the surface of 38CrMoAl by laser cladding synchronous powder feeding technology.Optical Microscopy(OM),scanning electron microscope(SEM),X-ray diffraction(XRD),energy spectrum analyzer(EDS),Vickers hardness tester and friction tester were used to systematically characterize the phase,microstructure,wear and corrosion resistance of high entropy alloy coating.The results show that the addition of Ti and Al element promotes the transformation of coating phase structure from face centered cubic structure(FCC)to body centered cubic structure(BCC),change to BBC+FCC phase.Al is more effective in promoting the formation of BCC phase in high entropy alloy and making BCC phase become the dominant phase of the alloy.The addition of Ti and Al makes the dendrite structure of the cladding zone finer and the dendrite spacing smaller.FeCoCrNiAlCu_(0.3)has higher microhardness,up to 683.5 HV0.3.The effect of Ti and Al on the wear resistance of high entropy alloy coating is similar to that of hardness,FeCoCrNiAlCu_(0.3)shows better wear resistance.The wear mechanism of the coating changes from fatigue wear to abrasive wear with the addition of Al.The addition of Ti makes the wear mechanism of the coating completely change into fatigue wear.Ti and Al elements have the opposite trend to promote the transformation of wear mechanism.