Evaluation of Interface and Residual Strain of NiTi Layer Deposited on NiTiX Substrate by Laser Powder Bed Fusion

• DOI: 10.1002/adem.202400002
• Publication Date: 2024-04-12T03:33:41Z
• Authors: Mahshid Memarian; Maryam Mohri; Mahbod Golrang; Christian Leinenbach; Irene Ferretto; Elyas Ghafoori; Mahmoud Nili‐Ahma...
• Keywords: Nickel titanium; Interface (matter); Strain (injury)

This study investigates the microstructure and properties of functionally graded NiTi alloy bilayers. The layer is printed by laser powder bed fusion on a NiTiX (where X Hf or Cu) substrate prepared vacuum arc remelting. Specimens produced with different thicknesses layers, but constant thickness ratio, are examined optical scanning electron microscopy prior to postannealing process at 1000 °C for 16 h. Scanning microscopy– energy‐dispersive X‐ray spectroscopy transmission studies reveal presence Ti 2 Ni 4 3 precipitates in as‐printed NiTi/NiTiCu samples type NiTi/NiTiHf. Digital image correlation quantifies residual strain bilayer enables relief be monitored during heating. It has been shown that microcracks occurring along interfacial zones diminished after annealing heat treatment. microcrack closure occurs diffusion third elements open microcracks, leading precipitation accumulation interfaces. Eventually, sample displays two‐way shape memory effects about 24.5% recovery. work enhances understanding controlling fabrication yield tailored additively manufactured NiTi‐based materials.