Densification,microstructural features and tensile properties of selective laser melted AlMgSiScZr alloy from single track to block specimen

选区激光熔化成形AlMgSiScZr合金的致密度、组织及拉伸性能

The selective laser melting(SLM)processed aluminum alloys have already aroused researchers’attention in aerospace,rail transport and petrochemical engineering due to the comprehensive advantages of low density,good corrosion resistance and high mechanical performance.In this paper,an Al-14.1Mg-0.47Si-0.31Sc-0.17Zr alloy was fabricated via SLM.The characteristics of single track at different process parameters,and the influence of hatch spacing on densification,microstructural features and tensile properties of block specimens were systematically studied.The hatch spacing has an influence on the overlap ratio of single track,and further affects the internal forming quality of printed specimen.At a laser power of 160 W and scanning speed of 400 mm/s,the densification of block specimen increased first and then decreased with the increase of hatch spacing.The nearly full dense specimen(98.7%)with a tensile strength of 452 MPa was fabricated at a hatch spacing of 80μm.Typical characteristics of dimple and cleavage on the tensile fracture of the AlMgSiScZr alloy showed the mixed fracture of ductility and brittleness.

选区激光熔化制备铝合金零件具有密度小,耐蚀性好和力学性能高等优势,现已在航空航天、轨道交通和石油化工领域引起广泛关注。本文对Al-14.1Mg-0.47Si-0.31Sc-0.17Zr合金进行了选区激光熔化打印,并研究了不同工艺参数对单道试样的成形特性,以及块体试样致密度、微观组织及拉伸性能的影响规律。扫描间距对单道试样搭接率和块体试样内部质量具有显著影响。在激光功率160 W,扫描速度400 mm/s时,块体试样致密度随着扫描间距的增加呈现先升高后降低的变化趋势。当扫描间距为80μm时,试样致密度达到最大(98.7%),抗拉强度为452 MPa。拉伸断口表面存在韧窝和解理台阶,AlMgSiScZr合金断裂模式为韧-脆混合断裂模式。