Impact toughness of wire arc additive-manufactured SS321 stainless steel at elevated temperatures: An instrumented Charpy analysis

Abstract

This study employs instrumented Charpy impact testing to evaluate the temperature-dependent impact toughness of wire arc additive-manufactured SS321 stainless steel at room temperature, 100 °C, and 200 °C under dynamic loading conditions. Compared to room temperature, the absorbed energy increased by 59.9% at 100 °C (62.4 J) and 89.7% at 200 °C (73.5 J). Impact toughness improved by 64.8% (1798 kJ/m²) at 100 °C and 87.4% (2045 kJ/m²) at 200 °C. Crack initiation energy increased by 2.89 times from room temperature (10.9 J) to 100 °C (31.5 J). In comparison, crack propagation energy increased by 74.6% from 28.08 to 49.01 J at 200 °C. To identify the failure modes, fractured specimens were subjected to fractographic analysis. At room temperature, more brittle fractures were obtained, while increasing the testing temperature induces ductile fractures. The findings provide insights into the elevated-temperature performance of wire arc additive-manufactured SS321 for critical applications.