• Yao, Xiyu
• Popovich, Vera
• Borisov, Evgenii
• Hermans, Marcel
• Ding, Zhaoying
• Brouwer, Johannes C.
• Zhu, Jianing
• Popovich, Anatoly

Abstract

The pursuit of enhancing NiTi superelasticity through laser powder bed fusion (L-PBF) and [001] texture creation poses a challenge due to increased susceptibility to hot cracking in the resulting microstructure with columnar grains. This limitation restricts NiTi's application and contributes to material waste. To overcome this, we introduce a pioneering approach: utilising spark plasma sintering (SPS) to heal directional cracks in [001] textured L-PBF NiTi shape memory alloy. Diffusion bonding and oxygen utilisation for Ti 2 NiO x formation was found to successfully heal the cracks. SPS enhances mechanical properties, superelasticity at higher temperatures, and two-way shape memory strain during thermomechanical cycling. This work provides an alternative solution for healing cracks in L-PBF parts, enabling the sustainable reuse of cracked materials. By implementing SPS, this approach effectively addresses hot cracking limitations, expanding the application potential of L-PBF NiTi parts while improving their functional and mechanical properties. ; Team Vera Popovich ; Team Marcel Hermans

Topics

• grain
• Oxygen
• crack
• selective laser melting
• texture
• susceptibility
• sintering