选区激光熔化Zr改性Al-Si-Mg合金组织和力学性能

Microstructure and mechanical properties of Zr modified Al-Si-Mg alloy produced by selective laser melting

摘要:

针对选区激光熔化（SLM）高Mg含量AlSiMg3合金成形性差的缺点，通过Zr进行合金化，系统研究了工艺参数对SLM成形高Mg含量Al-Si-Mg-Zr合金的成形性及时效处理对合金组织和力学性能的影响。结果表明，SLM成形Al-Si-Mg-Zr合金的熔池边界处形成了大量的细小等轴晶，从而有效避免了样品在成形过程中裂纹的产生，增加了样品的SLM成形性，不同激光功率和激光扫描速度下获得样品的孔隙率均低于0.3%。拉伸测试结果表明，成形态样品的屈服强度（YS）为426±8 MPa，极限抗拉强度（UTS）为464±12 MPa。经165 ℃时效处理后，由于α-Al晶粒内部纳米强化相的增多，样品的强度增加明显，时效样品的最大YS和UTS分别为482±11 MPa和522±10 MPa。本研究获得SLM成形Al-Si-Mg-Zr样品的强度高于目前商用的SLM成形Al-Si-Mg合金。

Abstract:

The present study is devoted to research the effect of process parameters on processability, and aging treatment on microstructure and mechanical properties of selective laser melting (SLM) high Mg-content Al-Si-Mg-Zr alloy. The results show that alloy forms a large number of fine equiaxed grains at the boundary of the molten pool, which can avoid the generation of cracks during the SLM forming process and increase the processability of the sample. The porosity of the samples obtained under different process conditions is less than 0.3%. The yield strength (YS) and ultimate tensile strength (UTS) of the as-built samples are 426 ± 8 MPa and 464 ± 12 MPa respectively. After aging treatment, due to the increase in the number of nanoparticles embedded in α-Al cells, the strength of the sample increases obviously. The maximum YS and UTS of aged samples reach 482 ± 11 MPa and 522 ± 10 MPa, respectively. The strength of present samples is much higher than that of commercial SLM-formed Al-Si-Mg alloy.