Study on the Microstructure of Micro Laser Welded Joint of TiNi Shape Memory Alloy Sheet

Abstract:

Butt welding of 0.2mm thick TiNi shape memory alloy sheet was successfully realized by using micro impulse laser whose average power is 80W and the microstructure of welded joint was study in this paper. The results show that, the welded joint of micro laser welding can be divided into four zones according to grain size and microstructure. The microstructure in base metal zone is rolled structure and the grains are coarse and heterogeneous. The microstructures of welded seam center zone are fine equiaxed crystals and the microstructures of both lower surface and upper surface edge zone are columnar crystals. There is almost no obvious coarse grain heat-affected zone at the edge between welded seam and base metal. There is obvious segregation layer in local area of welded seam because the content of Ti and Ni elements is changed and different with base metal during the crystallizing course of welding pool.

• Periodical: Advanced Materials Research (Volumes 97-101)
• Pages: 3936-3939
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.97-101.3936
• Online since: March 2010
• Authors: Yu Hua Chen, Li Ming Ke, Ying Liu, Shi Long Xu
• Keywords: Micro Impulse Laser Welding, Microstructure of the Welded Joint, Smart Materials, Smart Structure, TiNi Shape Memory Alloy

References

[1] Kazuhiro Otsuka, Xiaobing, Ren: Intermetallics Vol. 7 (1999), p.511.

[2] Hirose A, Araki N: Metals Vol. 59 (1989) : p.61.

[3] Yuelan XU, Zhifu CHENG and Xiaolong FAN : Transactions of the China Welding Institution Vol. 27(2006) : p.26.

[4] Songbai XUE, Xiao chun LV and Huiwen ZHANG: Transactions of the China Welding Institution, Vol. 25(2004): p.1.

[5] Songbai XUE, Xiaochun LV, Yan CHEN: Transactions of the China Welding Institution Vol. 25(2004): p.7.

[6] Hsu Y T, Wang Y R, Wu S K: Metallurgical and Materals Transactions A Vol. 32(2001): p.569.

[7] Tuissi A, Besseghini S, Ranucci T: Materials Science and Engineering A Vol. 273-275(1999): p.813.

[8] Yuhua CHEN, Liming KE, Shilong XU: Hot Working Technology Vol. 38(2009).