Effect of Ti and B on the Wartensitic Transformations and Microstructures in Polycrystalline Cu-12(wt. %) Al-4(wt. %) Ni High Temperature Shape Memory Alloys

Abstract

Shahadat Hussain, Abhishek Pandey, Ashish Kumar Jain and Rupa Dasgupta

Addition of grain refiners/alloying elements is one of the most effective methods to reduce the grain size in the alloys, thereby, enhancing the mechanical and other properties of the alloy. Titanium and boron are added to polycrystalline Cu-12Al-4Ni (wt. %) high temperature shape memory alloy in the present study which were synthesized using induction melting furnace in air atmosphere. The alloys were betatized for one hour at temperature of 920°C and then were quenched in iced water. Further, they were characterized using the techniques of optical microscopy, X ray diffractometry, differential scanning calorimetry and hardness testing. Boron added alloys show thick plates of β1 ’ martensite with increase in transformation temperature as compared to base alloy whereas titanium added alloys show mixture of fine and thick plates of β1 ’ as well as γ1 ’ martensite with decrease in the transformation temperature as compared to the base alloy. Precipitation of second phase takes place in both titanium and boron alloying to CuAl-Ni base alloys.

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