The impact response and microstructural evolution of 316L stainless steel are examined at strain rates ranging from 1 × 103 to 5 × 10 3 s -1 and temperatures between 298 K and 1073 K (25 °C and 800 °C) using a split Hopkinson pressure bar and transmission electron microscopy (TEM). The results show that the flow behavior, mechanical strength, and work-hardening properties of 316L stainless steel are significantly dependent on the strain rate and temperature. The TEM observations reveal that the dislocation density increases with increasing strain rate but decreases with increasing temperature. Moreover, twinning occurs only in the specimens deformed at 298 K (25 °C), which suggests that the threshold stress for twinning is higher than that for slip under impact loading. Finally, it is found that the volume fraction of transformed α′ martensite increases with increasing strain rate or decreasing temperature. Overall, the results suggest that the increased flow stress observed in 316L stainless steel under higher strain rates and lower temperatures is determined by the combined effects of dislocation multiplication, twin nucleation and growth, and martensite transformation.
|Number of pages||8|
|Journal||Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science|
|Publication status||Published - 2012 Nov 1|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys