Microstructure, residual stress and tensile properties control of wire-arc additive manufactured 2319 aluminum alloy with laser shock peening

• Published in: Journal of alloys and compounds 2018-05, Vol.747, p.255-265
• Main Authors: Sun, Rujian, Li, Liuhe, Zhu, Ying, Guo, Wei, Peng, Peng, Cong, Baoqiang, Sun, Jianfei, Che, Zhigang, Li, Bo, Guo, Chao, Liu, Lei
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Aluminum base alloys; Compressive strength; Dislocation density; Grain size; Laser shock peening; Laser shock processing; Microhardness; Microstructure; Peening; Production methods; Quality control; Residual stress; Shot peening; Surface treatment; Tensile properties; Tensile strength; Wire; Wire-arc additive manufacturing
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.02.353

Wire-arc additive manufacturing can fabricate components with complex geometries efficiently compared with other manufacturing methods. However, the uncontrolled grain size and tensile residual stress in as-fabricated components have limited their applications. In this study, laser shock peening, an innovative surface treatment technique, was specially-combined with wire-arc additive manufacturing to refine microstructure, modify stress state and enhance tensile properties of as-printed 2319 aluminum alloy. After peening, the average grain size decreased from 59.7 μm to 46.7 μm, and the percentage of grains with low angle boundaries increased from 34% to 70%. High density of dislocations and mechanical twins were generated and resulted in the increase of micro-hardness. Residual stresses were modified from tensile to compressive state with a maximum value around 100 MPa. Yield strength was remarkably increased by 72%. This combined printing and peening manufacturing strategy provides microstructure and quality control of manufactured components for practical applications. [Display omitted] •Laser shock peening and wire arc additive manufacturing are specially-combined.•Grain refinement with higher percentage of low angle boundaries is achieved.•Tensile residual stresses are modified to beneficial compressive residual stresses.•Yield strength is remarkably increased by 72%.