选区激光熔化成形AlSiMg3合金

AlSiMg3 Alloy Formed by Selective Laser Melting

摘要:

基于选区激光熔化（SLM）技术熔体快速冷却的特点，通过提高Al-Si-Mg合金中Mg的含量，设计获得SLM技术专用AlSiMg3合金。系统研究了不同工艺参数和时效处理条件对SLM成形AlSiMg3合金组织和硬度的影响。结果表明，SLM成形样品均由α-Al、Si和Mg2Si相构成。高激光能量密度有利于增加粉末样品的成形性，当激光功率为160 W，扫描速度为200 mm/s时，样品具有最低孔隙率0.07%。随着激光扫描速度的增加，样品中富Si组织的比例逐渐升高，Mg元素在α-Al中固溶量逐渐增大，使得SLM成形样品的硬度逐渐升高，最大值为194±3 HV。样品经150 ℃时效处理后，由于α-Al内部纳米颗粒的析出，导致样品硬度增大，最大值为210±2 HV，远高于现有报道的SLM成形Al-Si和Al-Si-Mg铝合金。本研究报道了成形性和力学性能优异的SLM专用Al-Si-Mg合金。

Abstract:

A high Mg-content Al-Si-Mg3 aluminium alloy was designed for SLM based on the technical characteristics of the liquid quenching in SLM. The effect of the process parameters and aging treatment on the microstructure and the hardness of the SLM-formed AlSiMg1.5 alloy were systematically studied. The results show that all SLM-formed samples are composed of α-Al, Si and Mg2Si phases. High laser energy density is beneficial to increase the formability of the samples. The minimum porosity ~ 0.07% is obtained for the sample fabrication at a laser power of 160 W with a scanning speed of 200 mm/s. The Mg element dissolved in α-Al and the proportion of Si-rich microstructures increases with the increase of the scanning speed, as a result, the hardness of the SLM-formed samples increases gradually. The maximum hardness of the SLM-formed sample reaches 194±3 HV. The hardness increases obviously after aging treatment the SLM-formed samples at 150 ℃ for different times due to the precipitation of nanoparticles. The maximum hardness of the samples is 210 ± 2 HV, which is much higher than the reported SLM-formed Al-Si and Al-Si-Mg alloys. A special Al-Si-Mg alloy for SLM with excellent formability and mechanical properties was reported in this paper.