Microstructure and Mechanical Properties of AA7075 Alloy with Laser High-Temperature Pre-precipitation Process

The effect of laser high-temperature pre-precipitation on the microstructure and mechanical properties of the AA7075 alloy was studied comprehensively. Laser high-temperature pre-precipitation method was a promising alternative to the traditional high-temperature pre-precipitation method. The microstructure of the alloy was analyzed by transmission electron microscopy. By comparing the results of the hardness, tensile, and wear tests, the best mechanical properties of the alloy were obtained after treated with the 1000 W laser. More meta-stable η′ phases were formed in the matrix, in which the precipitates were dispersed. As for the mechanism, the interaction between dislocations and precipitates in the matrix changed from cutting mechanism to Orowan mechanism.