Surface integrity of heat treatable magnesium alloy AZ80A after cavitation peening

Abstract

The present paper aims to investigate topographical behavior of precipitation hardened magnesium alloy AZ80A subjected to cavitation peening. The introduction of surface residual compressive stress is the main feature of this new method, which is different from the traditional mechanical processing method and is also the key factor leading to the good service performance of the metal material surface. The tested material was heat treatable magnesium alloy AZ80A. Magnesium alloys have the lowest density among the common non-ferrous alloys and so are very important in reducing the weight and are used in many fields, including aviation, aerospace, electronics and automobile industries. After heat treatment of the magnesium alloy, cavitation peening was performed, which in all cases raises the surface hardness of the specimens. Cavitation peening also has a beneficial effect on compressive residual stresses, as they increase in all cases. It should be noted that in all specimens throughout the entire measurement depth the residual stresses stayed in compressive nature. They are especially expressed in the case of artificial aging, where we also achieve the maximum stress on the specimen surface in the amount of −220 MPa. The most negative thing about such a process is the surface roughness after cavitation hardening as it is greatly increased in all cases.

Keywords

• Magnesium alloy AZ80A
• Cavitation peening
• Artificial ageing
• Residual stresses
• Microhardness
• Surface roughness