Residual stresses in TiPdNi base thin film shape memory alloys

TiPdNi thin films with less than 2 μm thickness were produced using ion beam assisted deposition (IBAD) on heated and unheated substrates. Films deposited on unheated substrates were found to be amorphous, and subsequently annealed to induce crystallization. Residual stresses in the films were evaluated using the Stoney equation after deposition, and after annealing. Films deposited using IBAD on unheated substrates were found to have slight compressive stress (−22.4 MPa) while films deposited on heated substrates had a moderate tensile stress (176.2 MPa). Annealed films experienced extensive tensile stress (598.3 MPa), resulting in film failure.