Abstract Experimental investigations on cracking susceptibility were carried out for wire + arc additively manufactured (WAAM) Al-Cu-Mg alloys, which were designed and deposited with Al-Cu and Al-Mg wires in tandem. The influence of composition, heat input, mechanical properties and microstructure on cracking for ternary WAAM Al-Cu-Mg alloys were studied, aiming at minimizing cracks during deposition. Both macro and micro cracks were observed and identified to be inter-granular solidification cracks. The contour map of cracking susceptibility as functions of Cu and Mg contents was constructed, revealing that the composition range within Cu 4.2%–6.3% and Mg 0.8%–1.5% is less susceptible to cracks during solidification terminating in an isothermal ternary eutectic reaction. Higher micro hardness generally reduces the cracking susceptibility. Contour maps about thermal effects during deposition indicate higher wire feed speed causes higher heat input but lower density for deposited alloys, remarkably increasing solidification cracks. Peak susceptibility appears when micro hardness is lower than 95 HV and heat input is greater than 200 J/mm. Micro cracks may initiate from the inter-layer equiaxed grains zone for WAAM alloys if insufficient liquid feeding dominates during deposition. The proposed model can predict solidification cracking tendency for WAAM Al-Cu-Mg alloys.

中文翻译：

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具有串联焊丝和脉冲电弧的增材制造Al-Cu-Mg合金的设计和开裂敏感性

摘要 对焊丝+电弧增材制造（WAAM）Al-Cu-Mg合金进行了开裂敏感性实验研究，该合金由Al-Cu和Al-Mg焊丝串联设计和沉积。研究了成分、热输入、机械性能和微观结构对三元 WAAM Al-Cu-Mg 合金开裂的影响，旨在最大限度地减少沉积过程中的裂纹。观察到宏观和微观裂纹并确定为晶间凝固裂纹。构建了作为 Cu 和 Mg 含量函数的开裂敏感性等高线图，表明在等温三元共晶反应终止的凝固过程中，Cu 4.2%–6.3% 和 Mg 0.8%–1.5% 的成分范围不太容易出现裂纹。较高的显微硬度通常会降低开裂敏感性。关于沉积过程中热效应的轮廓图表明，较高的送丝速度会导致较高的热量输入，但沉积合金的密度较低，从而显着增加了凝固裂纹。当显微硬度低于 95 HV 且热输入大于 200 J/mm 时出现峰值磁化率。如果在沉积过程中液体供给不足占主导地位，则微裂纹可能从 WAAM 合金的层间等轴晶粒区开始。所提出的模型可以预测 WAAM Al-Cu-Mg 合金的凝固开裂趋势。如果在沉积过程中液体供给不足占主导地位，则微裂纹可能从 WAAM 合金的层间等轴晶粒区开始。所提出的模型可以预测 WAAM Al-Cu-Mg 合金的凝固开裂趋势。如果在沉积过程中液体供给不足占主导地位，则微裂纹可能从 WAAM 合金的层间等轴晶粒区开始。所提出的模型可以预测 WAAM Al-Cu-Mg 合金的凝固开裂趋势。