Wang Shuai, Gu HuiMin, Wang Wei, Li ChengDe, Ren Ling Ling, Wang Zhen Biao, Zhai YuChun, Ma PeiHua
School of Metallurgy, Northeastern University, Shenyang, China.
Inner Mongolia Metal Material Research Institute, Baotou, China.
3D Print Addit Manuf. 2020 Feb 1;7(1):28-36. doi: 10.1089/3dp.2019.0176. Epub 2020 Feb 13.
Al-Cu-Sn alloy deposits with different Sn contents were prepared by the wire and arc additive manufacturing process. The microstructure and mechanical properties of the deposits were examined by metallography, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and tensile tests. The results indicated that the addition of Sn significantly refined the microstructure of the deposits in their as-deposited state, and the grains were transformed from dendrites to equiaxed crystals with a uniform grain size of ∼30 μm. For the deposits with Sn ≥0.15%, the continuous and elongated θ phase on the grain boundary became block-shaped, and the size of the precipitated phase increased. After T6 heat treatment, the θ phase completely dissolved in the substrate in the deposits with Sn ≤0.1%, whereas the θ-phase solid dissolution was incomplete in the deposits with Sn ≥0.15%; the higher the Sn content, the greater the amount of θ phase remaining. After the T6 treatment, the deposits with an Sn content of 0.25% exhibited cracks distributed along the grain boundaries. The addition of Sn significantly increased the density of the θ' phase, which was diffused and uniform in size; with an increase in the Sn content, the distribution density of the θ' phase in the deposits first increased and then decreased as the peak-aging condition was reached. The addition of Sn could effectively improve the mechanical properties of the deposits, which first increased and then decreased with an increase in the Sn content. The mechanical properties of the deposits were optimal at an Sn content of 0.1%, with a tensile strength of 493 MPa, yield strength of 434 MPa, and elongation of 9.5%.
采用电弧增材制造工艺制备了不同Sn含量的Al-Cu-Sn合金熔敷层。通过金相显微镜、扫描电子显微镜、能谱仪、透射电子显微镜以及拉伸试验对熔敷层的微观结构和力学性能进行了研究。结果表明，添加Sn显著细化了熔敷层沉积态的微观结构，晶粒从树枝晶转变为等轴晶，平均晶粒尺寸约为30μm。对于Sn≥0.15%的熔敷层，晶界处连续且细长的θ相变为块状，析出相尺寸增大。T6热处理后，Sn≤0.1%的熔敷层中θ相完全溶解于基体，而Sn≥0.15%的熔敷层中θ相的固溶不完全；Sn含量越高，剩余的θ相越多。T6处理后，Sn含量为0.25%的熔敷层沿晶界出现裂纹。添加Sn显著增加了θ'相的密度，其弥散分布且尺寸均匀；随着Sn含量的增加，熔敷层中θ'相的分布密度先增大后减小，直至达到峰值时效状态。添加Sn可有效提高熔敷层的力学性能，力学性能随Sn含量增加先升高后降低。当Sn含量为0.1%时，熔敷层的力学性能最佳，抗拉强度为493MPa，屈服强度为434MPa，伸长率为9.5%。
