Plastic deformation on the free surface in the vicinity of the crack in AZ magnesium alloys

摘要

Purpose: Of this paper was to study plastic deformation of three magnesium alloys of the AZ series loaded very slowly with the aim to reveal mechanisms of plastic damage and fracture. Design/methodology/approach: Samples of a prismatic shape were provided with the V notch and deformed in the three point bending test. The samples were only slowly loaded and the test was interrupted at the moment when the main crack passed several millimetres. The nearest neighbourhood of the crack was studied by means of the light and scanning electron microscopy. Findings: Displays of plastic deformation on the samples free surface and an interaction of deformation bands with twins were found as the main characteristic features. Analysis of the fracture surfaces showed the influence of precipitates on the fracture properties. Research limitations/implications: Experiments were performed only on as cast materials. Practical implications: Technical praxis requires analysing reasons for damage of machine components, machine crashes in the traffic. Knowledge of the deformation and fracture mechanisms may contribute to solve these technical and economy problems. Originality/value: Presented results are original; they were not published and not considered for any publication in the future.