Due to exceptional strength/stiffness to weight ratio, aluminum (Al) alloys are being extensively used in many exclusive applications. The microstructure, and consequently, the mechanical properties of additively manufactured (AM) Al alloys are expected to vary compared to those of their conventionally manufactured counterparts due to the unique thermal history experienced during the additive manufacturing (AM) processes. Therefore, it is critical to understand the microstructure and characterize the mechanical properties of AM Al alloys to verify if they meet the requirements for being deployed in the fatigue critical applications. In this study, the microstructure and mechanical properties (i.e., tensile and fatigue) of laser beam powder bed fused (LB-PBF) LPW AlSi10Mg, EOS AlSi10Mg, Scalmalloy, and QuesTek Al alloys are characterized. Room temperature quasi-static tensile tests are conducted at the strain rate of 0.001 s⁻¹ on machined surface specimens, and uniaxial fully-reversed strain-controlled fatigue tests are performed on both as-built and machined surface specimens. Some differences in microstructure and tensile properties of the LB-PBF AlSi10Mg fabricated with LPW and EOS powders are noticeable. Among the Al alloys, the LB-PBF Scalmalloy possesses the highest strength and high ductility as well as the highest fatigue resistance credited to its ultrafine/nano-size grains and precipitates. For all the LB-PBF Al alloys investigated, surface micro-notches and volumetric defects (pores, lack of fusion) are found to be the primary sources of fatigue crack initiation in the as-built and machined surface conditions, respectively.

由于出色的强度/刚度与重量比，铝（Al）合金被广泛用于许多专有应用中。由于在增材制造（AM）过程中经历了独特的热历史，因此与常规制造的合金相比，增材制造（AM）铝合金的微观结构以及相应的机械性能预计会发生变化。因此，至关重要的是要了解AM Al合金的微观结构并表征其机械性能，以验证它们是否满足在疲劳关键应用中部署的要求。在这项研究中，表征了激光束粉末床熔合（LB-PBF）LPW AlSi10Mg，EOS AlSi10Mg，Scalmalloy和QuesTek铝合金的显微组织和力学性能（即拉伸和疲劳）。在机械加工的表面试样上进行^-1测试，并对制成的和机械加工的表面试样进行单轴完全反向应变控制的疲劳测试。用LPW和EOS粉末制造的LB-PBF AlSi10Mg的微观结构和拉伸性能存在明显差异。在铝合金中，LB-PBF卡尔马洛伊合金具有最高的强度和高的延展性，并且由于其超细/纳米尺寸的晶粒和析出物而具有最高的抗疲劳性。对于所研究的所有LB-PBF铝合金，发现表面微缺口和体积缺陷（孔洞，缺乏熔合）分别是在建造和加工的表面条件下引起疲劳裂纹的主要来源。