Anomalous elastic hardening in Fe-Co alloys at high temperature

作者:Zhang Hualei*; Li Xiaoqing; Schonecker Stephan; Jesperson Henrik; Johansson Borje; Vitos Levente
来源:Physical Review B, 2014, 89(18): 184107.
DOI:10.1103/PhysRevB.89.184107

摘要

The elastic moduli of Fe1-cCoc (c <= 0.2) alloys are found to decrease strongly with increasing temperature, but show very weak alloying effects for both low-temperature ferromagnetic and high-temperature paramagnetic states. For temperatures slightly below and around the Curie temperature of Fe, Co addition significantly increases the elastic moduli. The variation of the tetragonal shear elastic constant upon 20% Co addition increases from a small negative value to more than 135% as the temperature rises from 0 to 1200 K. The expected elastic softening in the case of Al doping is not confirmed. Both anomalous trends are ascribed to the interplay between intrinsic chemical effects, magnetism, and temperature.