Behavior of die cast magnesium alloys subject to rapid deformation

摘要

The effect of strain rate on tensile properties of cold chamber die cast AZ91D, AM60B and AM50A test bars is reported. The strain rate was varied from 15 s{sup}-1to 130 s{sup}-1, a range typical of deformation and crash. All tests were done at room temperature. The properties measured include fracture elongation and ultimate tensile strength values. The results are discussed in terms of the work hardening characteristics and strain rate sensitivities of the materials, and parameters in a material model suggested by Johnson-Cook have been determined. It has been found that flowstress increases and that elongation is not affected by strain rates from 15 s{sup}-1to 130 s{sup}-1. The energy absorption during deformation increases therefore with the speed of deformation, emphasizing the positive properties of magnesium die cast alloys for safety related applications.