Phase stability, elastic properties and martensitic transformation temperature of Zr50Pd50–xRux alloys from first-principles calculations

Abstract

The phase stability, elastic properties and martensitic transformation temperature of Zr50Pd50–xRux (x = 0, 6.25, 12.5, 18.75) alloys have been investigated by first-principles calculations based on density functional theory. The formation energy results show that the alloying Ru tends to occupy the Pd site in ZrPd alloy. The lattice constants of the austenite phases decrease with increasing Ru content, which is in accordance with the experimental results. According to the calculations of total energy difference between the austenite and martensite phases, the martensitic transformation temperature of Zr50Pd50–xRux (x = 0, 6.25, 12.5, 18.75) alloys decreases with increasing Ru content. From the formation energy and electronic structure, the increase of the Ru content in Zr50Pd50–xRux alloys can further stabilize the austenite phases but decrease the stability of the martensite phases at the same time. The B/G ratios of the Zr50Pd50–xRux alloys indicate that all the Zr50Pd50–xRux alloys are ductile. Moreover, the lower martensitic transformation temperature can be attributed to the stronger Zr–Ru hybridization interaction as compared to the Zr–Pd one.