Cracking behavior in the transitional region of laser-clad coatings on Al-Si alloy under multiple impact loading

摘要

An experiment was designed to investigate the cracking behavior in the transitional region of laser-clad iron-base alloy and bronze coating on an Al-Si alloy under multiple impact loading. The concept of transitional crack ratio (TCR) was introduced to evaluate the crack resistance of the transitional region to multiple impact loading (simply called impact resistance). The results showed that the microstructure of the transitional regions and the impact resistances of both types of coating were significantly influenced by laser cladding process parameters (substrate temperature for the iron-base alloy and scanning velocity for the bronze). The laser-clad iron-base alloy coatings with the highest impact resistance were obtained at substrate temperatures between 275 and 320 deg C, while the equivalent laser-clad bronze coatings were produced using the scanning velocities in the range 10-12 mm s~(-1). The study also included analysis of the cracking mechanism in the transitional regions of the two kinds of coating.