Strain strengthening method for high-temperature surface of magnesium alloy

Abstract

The invention provides a strain strengthening method for a high-temperature surface of magnesium alloy. The strain strengthening method comprises the following steps: (1) heating a material storage tank until a shot blasting medium reaches a required temperature; (2) after pressurizing air to be required pressure intensity by virtue of an air compressor, supplying air into a high-pressure air heating device through a conveying pipeline to obtain high-temperature and high-pressure gas; (3) heating a magnesium alloy sample to the required temperature; (4) blowing the shot blasting medium by virtue of high-temperature and high-pressure gas to hit the surface of the magnesium alloy sample. According to the strain strengthening method, the shot blasting is carried out by virtue of high-temperature and high-pressure gas, and the heating temperature of the magnesium alloy sample is between magnesium alloy aging temperature and a temperature which is 50 DEG C higher than the aging temperature, so that a starting non-basal slip system of the magnesium alloy sample is met, the plasticity of the magnesium alloy can be improved, the deformability can be improved, a relative high residual compressive stress is achieved, the stability of the residual stress can be improved, and the fatigue performance of the magnesium alloy can be improved; furthermore, a proper shot blasting window can be broadened, and the experimental operation is easily achieved.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy surface treatment, and in particular relates to a high-temperature surface deformation strengthening method of magnesium alloy. Background technique [0002] Fatigue fracture has always been the most important form of damage to mechanical parts and engineering components. In aerospace, shipbuilding, chemical machinery, transportation, engineering machinery and other fields, about 50-90% of structural strength damage is caused by fatigue damage. Magnesium alloy is a metal material with great development potential, and the improvement of fatigue performance is conducive to expanding its application field. Fatigue fracture of materials often starts from the surface, surface layer or subsurface layer, especially in the stress concentration area, thus improving the bearing capacity of the stress concentration area, strengthening the surface layer at a certain depth can significantly improve th...

AI Technical Summary

Problems solved by technology

However, unlike aluminum alloys and steels, magnesium alloys have a close-packed hexagonal crystal structure. At room temperature, only basal plane slip occurs in magnesium alloys, which can only provide three geometric slip systems and two independent slip systems. Slip occurs, still can not meet the requirements of the von Mises criterion

Therefore, magnesium alloys are difficult to deform at room temperature, have poor plasticity and toughness, and the hardness of the matrix is ​​low, and the surface is difficult to withstand severe plastic deformation. Although low-intensity shot peening can greatly improve fatigue performance, high-intensity shot peening will cause surface damage. Defects and microcracks, so the room temperature shot peening effect of magnesium alloys is limited