Effect of Hf content on martensitic transformation, microstructure, and mechanical properties of Cu50Zr50−xHfx alloys

• The Hf addition increases the martensitic transformation temperature and the thermal stability.
• The plasticity reduces due to the appearance of hard brittle second phase (Zr,Hf)2Cu.
• The elastic modulus of Cu50Zr50−xHfx alloys increases with increased Hf content.

The effect of Hf substituting for Zr of Cu50Zr50−xHfx alloys on the microstructure, martensitic transformation behavior, and mechanical properties is investigated. It is demonstrated that Cu50Zr50−xHfx alloys exhibit higher transformation temperature with a peak martensite reverse transformation temperature of 594 K for Cu50Zr42Hf8 alloy, smaller thermal hysteresis and better thermal stability in comparison to those of Cu50Zr50 alloy. Due to the appearance of hard brittle second phase (Zr,Hf)2Cu, the elastic modulus increases while the plasticity reduces with Hf substituting for Zr.