This paper presents an investigation into the high-velocity impact of 304L stainless steel gas tungsten arc welded (GTAW) joints at strain rates between 10-3 and 7.5×103 s-1 by using the compressive split-Hopkinson bar technique and transmission electron microscopy (TEM). The effects of strain rate on the flow response and microstructure evolution are fully evaluated. The variations of microstructure correlated with dynamic behaviour are presented and discussed for different loading conditions. The results show that the tested weldments exhibit a pronounced strain-rate sensitivity, and that changes in the strain rate result in a difference in the flow stress, fracture strain, and work hardening coefficient. Microstructural observations show that an increased strain rate increases the number of dislocations, the twin density, and the α′ martensite volume fraction. Furthermore, significant differences in the microstructures of the dislocations, twins, and α′ martensite formations are noted between the fusion zone and base metal regions over the entire strain-rate range considered in the present investigation. Finally, the significant increase of flow stress which is noted for an increased strain rate can be attributed to the contributions provided by the nature of the dislocations, twins, and α′ martensite in both the fusion zone and the base metal regions.
|Number of pages||10|
|Journal||Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao|
|Publication status||Published - 2003 Oct 1|
All Science Journal Classification (ASJC) codes
- Mechanical Engineering