Process Analysis and Friction Wear Performance Study of Laser Impact Strengthened MB8 Magnesium Alloy

Magnesium alloy due to its high specific strength, specific stiffness and good electrical conductivity, thermal conductivity and electromagnetic shielding properties and in the aerospace, weapons industry, nuclear industry and other military high-end fields have been widely used, known as the "21st century green engineering materials". However, its low strength and hardness make it susceptible to wear and fatigue failure under complex service conditions, which seriously affects the safety and reliability of the structure. Laser impact peening is a surface modification technique that uses the force effect of laser-induced shock waves to cause plastic deformation and residual compressive stress in metallic materials, thereby improving the overall mechanical properties of the material. This paper investigates the effect of laser impact peening on the wear and fatigue resistance of MB8 magnesium alloy. The main research work and conclusions are as follows.1. The changes in surface morphology and roughness of MB8 magnesium alloy during laser impact with different impact parameters. The roughness of the impact area was found to be positively correlated with the laser power density and negatively correlated with the lap rate, while the roughness showed a trend of decreasing and then increasing when the number of impacts was 1, 2 and 3 times respectively. 2, using different impact parameters of laser impact when the MB8 magnesium alloy hardness change law. After the laser impact treatment of magnesium alloy hardness significantly increased, the maximum increase in surface hardness of 30.2%, while the formation of a gradient hardening layer. As the hardness of the material increases its mass wear rate decreases significantly and the degree of wear resistance is improved significantly, with the average mass wear rate of the strengthened magnesium alloy decreasing by up to 28.73%. The hardening degree of the material increases with the increase of laser power density, lap rate and impact number, the impact number has the most obvious effect, the laser power density is the second, the lap rate has the weakest effect.3. The effect of laser impact on the tribological properties of magnesium alloys under different loads was investigated. After laser impact, the mass wear rate of the material is significantly reduced, and the wear resistance is significantly improved, and because the material is mainly abrasive wear under low load and low speed conditions, and laser impact can make the material hardness significantly increased, so its wear resistance strengthening effect is more obvious. However, under high load conditions the material wear process is accompanied by fatigue wear and thus the strengthening effect is limited.