Zhang Li, Ouyang Wentai, Wu Di, Sheng Liyuan, Guo Chunhai, Ma Licheng, Chen Zhihao, Zhu Zhenkai, Du Yongxiao, Cui Peijuan, Hou Zhanlin, Zhang Wenwu
School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
Key Laboratory of Aero Engine Extreme Manufacturing Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, CAS, Ningbo 315201, China.
Materials (Basel). 2023 Jun 24;16(13):4570. doi: 10.3390/ma16134570.
Repairing processing is a significant method for damaged high-cost Ti-6Al-4V components to decrease economic loss, which usually utilizes a welding technique. For a large-size structural component, welding processing is commonly completed in air conditioning, which makes it difficult to avoid welding defects. To this end, an appropriate matching technique is important for improving welding performance. In the present research, asynchronized laser shock peening (ALSP) and synchronized laser shock peening (SLSP) techniques were utilized to decrease the influence of macro welding defects on laser-welded Ti-6Al-4V joints. The results show that SLSP has a greater effect on inducing surface plastic deformation on Ti-6Al-4V joints with a pitting depth of more than 25 microns while ALSP can lead to a pitting depth of about 15 microns. Through micro-CT observation a long hot crack exists in the central area of as-welded joints with a length of about 2.24 mm, accompanied by lots of pores in different sizes on double sides. After ALSP processing, some pores are eliminated while others are enlarged, and one-side crack tips present closure morphology. However, some microcracks exist on the side-wall of hot cracks. With the influence of SLSP, significant shrinkage of pores can be observed and both sides of crack tips tend to be closed, which presents a better effect than ALSP processing. Moreover, greater effects of grain refinement and thermal stress release could be achieved by SLSP processing than ALSP, which can be ascribed to dynamic recrystallization. For the as-welded joint, the ultimate tensile strength (UTS) and elongation (EL) values are 418 MPa and 0.73%, respectively. The values of UTS and EL in the ALSP processed joint are increased to 437 MPa and 1.07%, which are 4.55% and 46.48% higher than the as-welded joint, respectively. Such values after SLSP processing are 498 MPa and 1.23%, which are 19.14% and 68.49% higher than the as-welded joint, respectively.
修复加工是减少高成本 Ti-6Al-4V 受损部件经济损失的一种重要方法，该方法通常采用焊接技术。对于大型结构部件，焊接加工通常在空调环境中完成，这使得难以避免焊接缺陷。为此，一种合适的匹配技术对于提高焊接性能至关重要。在本研究中，采用异步激光冲击喷丸（ALSP）和同步激光冲击喷丸（SLSP）技术来降低宏观焊接缺陷对激光焊接 Ti-6Al-4V 接头的影响。结果表明，SLSP 对 Ti-6Al-4V 接头表面塑性变形的影响更大，点蚀深度超过 25 微米，而 ALSP 可导致点蚀深度约为 15 微米。通过微 CT 观察发现，焊后接头中心区域存在一条长约 2.24 毫米的长热裂纹，两侧伴有大量不同尺寸的气孔。经过 ALSP 处理后，一些气孔被消除，而另一些气孔则被扩大，一侧裂纹尖端呈现闭合形态。然而，热裂纹侧壁上存在一些微裂纹。在 SLSP 的影响下，可以观察到气孔显著收缩，裂纹尖端两侧趋于闭合，这呈现出比 ALSP 处理更好的效果。此外，与 ALSP 相比，SLSP 处理能实现更大的晶粒细化和热应力释放效果，这可归因于动态再结晶。对于焊后接头，其抗拉强度（UTS）和伸长率（EL）值分别为 418 兆帕和 0.73%。ALSP 处理接头的 UTS 和 EL 值分别提高到 437 兆帕和 1.07%，分别比焊后接头高 4.55%和 46.48%。SLSP 处理后的这些值分别为 498 兆帕和 1.23%，分别比焊后接头高 19.14%和 68.49%。
