Effect of weld nugget size on failure mode and mechanical properties of microscale resistance spot welds on Ti–1Al–1Mn ultrathin foils

Authors

Feng Chen, Nanjing University of Aeronautics & AstronauticsFollow
Shiding Sun, University of Nebraska - LincolnFollow
Zhenwu Ma, Suzhou University of Science and Technology
G Q. Tong, Nanjing University of Aeronautics & Astronautics
Xiang Huang, Nanjing University of Aeronautics & Astronautics

Document Type

Article

Date of this Version

2018

Citation

Advances in Mechanical Engineering 2018, Vol. 10(7) 1–10

DOI: 10.1177/1687814018785283

Comments

Creative Commons CC BY:

Abstract

We use tensile–shear tests to investigate the failure modes of Ti–1Al–1Mn microscale resistance spot welds and to determine how the failure mode affects the microstructure, microhardness profile, and mechanical performance. Two different failure modes were revealed: interfacial failure mode and pullout failure mode. The welds that fail by pullout failure mode have much better mechanical properties than those that fail by interfacial failure mode. The results show that weld nugget size is also a principal factor that determines the failure mode of microscale resistance spot welds. A minimum weld nugget size exists above which all specimens fail by pullout failure mode. However, the critical weld nugget sizes calculated using the existing recommendations are not consistent with the present experimental results. We propose instead a modified model based on distortion energy theory to ensure pullout failure. Calculating the critical weld nugget size using this model provides results that are consistent with the experimental data to high accuracy.