扫描速度对选区激光熔化高强Al-Mg-Sc-Zr合金组织与性能的影响

Effect of Scanning Speed on Microstructure and Properties of Selective Laser Melting High Strength Al-Mg-Sc-Zr Alloy

采用选区激光熔化(SLM)技术在不同扫描速度工艺条件下制备了高强Al-Mg-Sc-Zr合金,采用了光学显微镜(OM)、扫描电子显微镜(SEM)、室温拉伸实验、室温摩擦磨损实验等方法,研究了激光扫描速度对合金微观组织和力学性能的影响。结果表明:当激光功率不变,扫描速度在1250~1850 mm/s时,随着扫描速度从1250 mm/s升至1850 mm/s,合金致密度和力学性能均呈现先升高后降低的趋势。当扫描速度达到1850 mm/s时,由于能量密度低导致粉末无法充分熔化,层间润湿不充足,形成大量不规则孔隙,降低了材料力学性能。选区激光熔化成形合金在不同扫描速度下均可以完成冶金结合,且致密度均高于98.9%,当扫描速度为1450 mm/s时,合金成形性能达到最优,致密度为99.87%,其屈服强度、抗拉强度和断后延伸率分别为379 MPa、420 MPa和17.0%,摩擦磨损实验表明其磨损量和磨损速度均为最低,耐磨性能显著优于其他参数。

Al-Mg-Sc-Zr alloys were prepared at different scanning speeds by selective laser melting(SLM).The effects of laser scanning speed on the microstructure and mechanical properties of the alloy were studied by means of optical microscopy(OM),scanning electron microscopy(SEM),Room temperature friction and wear test,and room temperature tensile experiments.The results show that when the scanning speed reaches 1850 mm/s,low energy density leads to insufficient melting of powder and inter-layer wetting,resulting in the formation of a large number of irregular pores,which reduces the mechanical properties of the material.Under the premise of constant laser power,the scanning speed range is controlled between 1250 mm/s and 1850 mm/s.As the scanning speed increased from 1250 mm/s to 1850 mm/s,the density and mechanical properties of the alloys increased first and then decreased.The alloys can complete metallurgical bonding at different scanning speeds,and the densities are higher than 98.9%.When the scanning speed is 1450 mm/s,the alloy formability is optimized,the density is 99.87%,the wear amount and wear speed are the lowest,the wear resistance is obviously better than other parameters,and the yield strength,tensile strength and elongation after fracture are 379 MPa,420 MPa and 17.0%,respectively.