Papers by Keyword: Strain-Amplitude

Abstract: Magnesium alloys are among the best light-weight structural material with a relatively high strength-to-weight ratio end excellent technological properties. Therefore, magnesium attracts special attention of researchers working in automotive and aircraft industry. This work paid the efforts to the structural components made out of magnesium alloy AM60 such as chassis, transmission case in automotive, where the components are subject to cyclic loading after being pre-loaded. In this study, the cyclic stress-strain behaviors were investigated by strain-controlled fatigue testing. In order to investigate the effects of R-ratio on mean stress relaxation, the R-ratio ranged from 0.1 to 0.7 at the strain amplitude of 0.3%. The experimental results indicate that the mean stress relaxation increases with the increasing R-ratio. A constitutive model was proposed to simulate the mean stress relaxation. The calculation results show that the constitutive model developed in this work is capable of reproducing the stress relaxation behaviors of magnesium alloy AM60 under strain control.

Abstract: Based on the damping alloy Fe-13Cr-6Al, five types of alloys are prepared in the present study with 1 at.% of Cr replaced by Mo, Mn or Nb, and 0.5 at.% of Al replaced by Cu. The effects of annealing temperature, vibrating frequency, strain-amplitude and static load on the damping capacity of these alloys are studied through damping capacity measurement and optical microscope observation. The following results were obtained: (1) The damping capacity of Fe-13Cr-6Al based alloys increases with increasing annealing temperature. (2) The replacing elements demonstrate different effects on the damping capacity of Fe-13Cr-6Al based alloys. The damping capacity of the alloys with Cu or Mn substitution increases, while that of alloys with Nb substitution decreases significantly as compared with Fe-13Cr-6Al. (3) The damping capacity of Fe-13Cr-6Al based alloys is not sensitive to frequency. It decreases with increasing in static load, and increases rapidly with strain before reaching a steady state.