Effect of building direction on high strain-rate compressive behavior of heat-treated LPBF-maraging steels using Split Hopkinson pressure bar apparatus

Abstract

Rod-shaped samples of maraging steel were additively fabricated in vertical and horizontal directions using laser powder bed fusion technique. The samples were first aged at 490 °C for 6 h and then subjected to dynamic compressive tests using Split Hopkinson Pressure Bar apparatus. The dynamic compression tests were conducted on vertical samples at strain rates of 190, 460, 810, 1100, 1300 s−1. However, the high strain rate tests were performed at strain rates of 120, 615, 745, 890, 2200 s−1 on horizontal samples. After applying the compressive impact loads on the samples, it was found that although horizontally built samples exhibit higher dynamic strength, vertically built samples show higher elongation during high-strain rate tests. Furthermore, fracture happened at a strain rate of 1300 s−1 for vertical samples. However, for horizontally built samples, failure occurred at the strain rate of 2200 s−1. Finally, the Johnson-Cook and Voyiadjis and Abed models, which take into account the contribution of strain softening and strain hardening were employed to simulate the high strain rate performance of vertical and horizontal maraging steels.