Shape memory behavior of NiTiHf alloys fabricated by selective laser melting

This study investigates the high-temperature shape memory behavior of NiTiHf alloys fabricated via selective laser melting process. Specifically, the effects of laser power (100 W and 250 W) on their transformation temperatures, strain, and microstructure were investigated and compared to the ingot. The transformation temperatures of SLM fabricated alloys increased from 150 degrees C to 350 degrees C with elevated laser power due to Ni evaporation. The sample fabricated with 100 W showed sharp transformation peaks, good shape memory behavior with recoverable strain of 1.67% and superelasticity. The sample fabricated with 250 W had broad transformation peaks with low recoverable strain of 0.7% during thermal cycling. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.