丝材成分对电弧增材Al-Cu合金组织及力学性能的影响

Influence of wire compositions on the microstructure and mechanical properties of WAAM Al-Cu aluminum alloy

摘要:

针对电弧增材制造Al-Cu合金力学性能非均匀问题,采用不同成分的丝材研究了Cu含量及Fe、Si杂质含量对热处理后成形组织及力学性能的影响。研究结果表明：Cu含量低(5.3 wt%),α(Al)基体中固溶Cu含量不足,成形试样屈服强度显著降低,Cu含量适中(5.8-6.5wt%),成形组织中残余少量θ相(Al₂Cu),对塑性影响较小,成形试样强度提高；在Cu含量适中、Si含量较低(ω(Si)<0.08wt%)时,随着Fe含量增加,成形组织中残余的块状或条状α(Fe)相增加,α(Al)基体中固溶Cu含量减少,成形试样屈服强度降低；在Cu含量适中,Fe、Si含量较高时(>0.15wt%),成形试样层间形成的针状β(Fe)相增加,垂直方向塑性显著降低；严格控制丝材中Fe、Si杂质含量(Si<0.08wt%,Fe<0.15wt%),Cu含量适中(5.8-6.5wt%),成形试样无明显各向异性,平均抗拉强度、屈服强度、断后伸长率分别超过440MPa、300MPa、10%。

Abstract:

The influence of wire compositions with different Cu, Fe and Si content on the microstructures and mechanical properties of heat treated WAAM single-walls was studied. It was found that the yielding strength of WAAM samples was low when the Cu content (5.3wt%) in wire was insufficient. When the Cu content in wire slightly exceeded the maximum solid solubility of Cu (5.65wt%) in α(Al), the yielding strength of WAAM samples increased without deteriorating the plasticity although there were some residual θ(Al₂Cu) phases. When the wire had approiate Cu content (5.8-6.5wt%) with low Si content(<0.08wt%), the yielding strength of WAAM samples decreased with the increasing of Fe content due to the redueced amount of strengthening phases and increased amount of θ phases and α(Fe) compounds. When the wire had approiate Cu content with high Fe and Si content(>0.15wt%), the plasiticity in vertical direction of WAAM samples deteriorated due to the existing of acicular β(Fe) compounds in the interlayer region of the samples. Using the wire with low inpurities content (Si<0.08wt%,Fe<0.15wt%) and approiate Cu content (5.8-6.5wt%), the WAAM samples possesed the excellent mechancial properits with average tensile strength, yielding strength and elongation after fracture exceeding 440MPa, 300MPa and 10%, respectively.