Influence of Ni Content on the Microstructure of Heat Treated Ti-Ni-Cu Shape Memory Alloys

This paper reportsthe influence of Ni content and heat treatment condition (solution annelaing and aging) on the microstructure of TiNiCu shape memory alloys. The wrought alloys were fabricated through vacuum arc melting, hot pressing, hot rolling and finally wire drawing. the wrouught alloys were solution annealed at 900oC for 0.5 h and water quenched. Another group of samples then subjected to subsequent aging at 400oC for 0.5 h following the solution annealing. The wrought alloys were finally subjected to standard metallographic preparation for characterization by using XRD, optical microscope and EDS. Experimental results showed that the substitution of Ni site by Cuin solution annealed Ti49.7-Ni41.1-Cu9.2 alloy revealed Ti2Ni peaks while maintaining the B19 and B2 peaks. IncReasing of Ni content with the expense of Ti content in the Ti44.4-Ni46.6-Cu9.0 alloys diminished the Ti2Ni peaks and revealed Ti0.4Ni0.565Cu0.035 phase. Further increasing of Ni content increased the peaks intensity of the Ti0.4Ni0.565Cu0.035 phase. Subsequent aging treatment subjected to solution annealed alloys slightly changed the diffraction peaks intensity of the phases in the alloys. The microstructure images resulted from optical microscope confirmed the phases formed in the alloys identified by XRD. Proceeding of International Conference on Physic and Aplications (ICOPIA 2012).