选区激光熔化制备Al_(0.5)CoCrFeNi高熵合金的工艺参数及组织性能

Processing Parameters,Microstructure and Properties of Al_(0.5)CoCrFeNi High Entropy Alloy Prepared by Selective Laser Melting

为了验证采用选区激光熔化(SLM)技术制备高熵合金的可行性,使用原始混合粉末进行了Al_(0.5)CoCrFeNi高熵合金的SLM制备。通过对相对密度进行表征,探讨了激光功率、扫描速度、扫描间距等工艺参数对成型质量的影响,并采用扫描电镜及X射线衍射仪等进行了显微组织、相组成分析,通过硬度和拉伸试验对材料的力学性能进行了表征。结果表明:激光功率、扫描速度、扫描间距三者间的交互作用对材料的相对密度有很大的影响,材料相对密度随着能量密度的增加而增加。SLM制备的高熵合金试样的相对密度最高可达99.92%,组织细小均匀,由简单的面心立方结构和体心立方结构两相构成,屈服强度达到540 MPa,拉伸强度达到878 MPa,延伸率为18%,综合性能优于传统熔炼高熵合金,表明采用SLM技术制备高熵合金是可行的。

Al05CoCrFeNi was prepared by laser selective laser melting(SLM),which can provide the feasibility of preparing high entropy alloys(HEAs)by in situ mixed powders.The influences of processing parameters such as laser power,scanning speed and hatch spacing on the relative density were discussed.The microstructure and crystal structure were investigated by scanning electron microscopy(SEM)and X ray diffraction(XRD),and the mechanical properties were also characterized.It is revealed that:1)the interactions between laser power,scanning speed and hatch spacing have great influences on the relative density,and the relative density increases with energy density,up to9992%;2)the HEA samples prepared by SLM possess a fine and uniform microstructure with simple FCC and BCC structures;3)at ambient temperature,the alloy shows a yield strength of540MPa,the maximum tensile strength could reach878MPa with an elongation18%;and4)compared with HEAs obtained by traditional preparing process,the alloy has more excellent microstructure and mechanical properties.