Effect of Zr content on mechanical properties of Ti-Ni-Zr shape memory alloy films prepared by dc magnetron sputtering

摘要

To further understanding of the effect of Zr content on the shape memory behavior of ternary Ti-Ni-Zr alloy films, ternary alloy films were deposited with various Zr contents using triple source dc magnetron sputtering. Deposited films annealed at 700 degrees C showed martensite transformation accompanied with shape memory behavior. Martensitic transformation start (Ms) temperature of the ternary alloy film was found to increase with increasing Zr content for a Zr content higher than 10 at%. The highest Ms temperature attained was similar to 170 degrees C for a Zr content of 19.5 at%. Critical stress against plastic deformation was found to increase with increasing Zr content up to 10 aft. Although further increase of Zr content caused embrittlement, the Ti32.3Ni48.2Zr19.5 film showed a shape memory effect with a recoverable strain of similar to 1.3% under a constant stress of 250 MPa. This indicates that the Ti-Ni-Zr alloy film is a promising candidate for cantilever type micro-actuators. (C) 2008 Elsevier Ltd. All rights reserved.