论文类型：期刊论文
第一作者：Kaiwen Wei
通讯作者：Zemin Wang
合写作者：Xiaoyan Zeng
发表刊物：Acta Metallurgica Sinica
收录刊物：SCI、EI
卷号：52
页面范围：184-190
发表时间：2016-02-11
影响因子：0.938
摘要：Magnesium alloys have attracted more attentions due to their low densities and excellent specific strengths. However, proper manufacturing methods are still needed to promote further applications of magnesium alloys due to the shortcomings of conventional processing methods. As one of the most promising additive manufacturing technologies, selective laser melting (SLM) was utilized to process the most commonly-used AZ91D magnesium alloy in this work. Element vaporization mechanism during the forming process and the influence of element vaporization on chemical composition, microstructure, and mechanical properties of the final products were investigated using OM, SEM, EDS, XRF and XRD. The results show that the relative content of Mg in the SLM-processed samples (86.61%-88.68%) was lower than that in the original AZ91D powders (90.63%), whereas the relative content of Al in the former ones (10.40%similar to 12.56%) was higher than its counterpart in the latter ones (8.97%). This variation matches well with the calculation by Langmuir model, demonstrating that element vaporization of AZ91D mainly targets at Mg. With the increase of laser energy density (Erg), weight ratio of Mg to Al (77) in the SLM-processed samples first increased, then decreased and finally tended to be constant. eta of the sample prepared at 55.6 J/mm(3) (sample No.8) presented a smallest difference with that of the original powders. A model illustrating analytic relationship between eta and E-v was established by mathematical regression with the fitting index R-2 being 0.858. The sample processed at 166.7 Jr/mm(3) (sample No.1) underwent one of the most remarkable compositional variation and exhibited a typical solidified microstructure similar to the die-cast AZ91D in which net-like beta-Mg17Al12 precipitates were distributed around the alpha-Mg matrix. However, beta-Mg17Al12 content as well as solid solubility of Al in alpha-Mg matrix was much higher in sample No. 1. The enhanced tensile strength and micro-hardness as well as the deteriorated elongation of sample No. 1 could be attributed to the composition variation during SLM process.