D. Ciccarelli

Compressive deformation of an Mg-Al-Si-RE alloy between 120 and 180 °C

Abstract The deformation behaviour of an Mg-Al-Si-RE (ASE210) alloy between 120 and 180 °C was investigated by means of uniaxial compression tests to identify possible differences in the deformation response compared with uniaxial tensile data. Early fracture was observed in the low-temperature/high strain rate regime, fracture occurring by crack propagation at 45° with respect to the compression axis. In the high-temperature/low strain rate regime, the flow curves exhibited the typical shape that is usually observed in materials where deformation is controlled by recovery of substructure. The peak flow stresses obtained in this regime of temperature and strain rate were compared with other data obtained by testing the same alloy in tension. The strength of the alloy was found to be slightly greater in compression than in tension, this difference gradually disappearing as strain rate decreased.

High Temperature Deformation of Wrought Zn-Containing Magnesium Alloys

The high temperature response in torsion and creep of two extruded Mg-Zn alloys was investigated in the present study. The alloy 0 (Mg-2Zn-1Mn) was found to exhibit a lower strength than the alloy 2 (Mg-0.55Zn-0.79Mn-0.75Al-0.17Ca), even if the activation energy for creep was similar for both materials (170-180 kJ/mol). The difference in flow stress was here preliminarily attributed to the precipitation of fine Al2Ca particles.

High temperature deformation of IN718 superalloy: use of basic creep modelling in the study of Nickel and single-phase Ni-based superalloys

Abstract A basic model was applied to pure Ni and then to a single-phase superalloy. The high temperature deformation of the superalloy, a solution treated IN718, was investigated by torsion testing in a high-temperature regime (1000–1100 °C) where no precipitation of secondary phases was expected. The material exhibited the classical behaviour of alloys which undergo dynamic recrystallization. The peak-flow stress dependence on strain-rate and temperature was described by a physically-based set of constitutive equations, which took into account both dislocation hardening and solid solution strengthening, and was previously successfully used for the description of creep deformation of Cu, Al alloys and austenitic steels. The model provided an excellent description of the experimental data and for this reason can be considered an excellent basis for further development, which should take into account the precipitation of secondary phases.