Evaluation of Nb-Ni Influence on the Mechanical Behavior in a Cu-Al-Be Shape Memory Alloy

Abstract

Aims: The objective was to investigate the modifications induced by grain refiners on microstructural and mechanical behaviour of Cu-Al-Be shape memory alloy. Study Design:  The experiment was conducted in a completely randomized design. Place and Duration of Study: the experiment was carried out at the Laboratory of Rapid Solidification of the Center Technology - CT, Federal University of Paraíba – UFPB, João Pessoa Campus, Paraíba, Brazil, between October 2017 and December 2018. Methodology: The alloys were prepared by induction melting and hot rolled into strips of 1.0 mm thickness at room temperature without protective atmosphere, followed of heat treatments. Subsequently the microscope analysis, differential scanning calorimetry (DSC), and mechanical tests were carried out. Results: The shape memory alloys produced present phase transformations corresponding to the superelastic effect (SE). Grain size reduced considerably with increases content of Nb-Ni. Additionally, the mechanical tensile testing and hardness tests verified that the addition of Nb-Ni increases the stress of the alloy. Conclusion: The manufactured of Cu-Al-Be alloys by induction melting and hot rolled without protective atmosphere is viable. The microstructure analysis shows the grain refinement in Cu-Al-Be alloys containing 1.0 wt% and 1.5wt% of Nb-Ni alloy with considerable reduction in grain size. The reduction in the grain size shows the improvement in the hardness and mechanical tensile properties.