Pulsed laser remelting non-resonant vibration assisted grinding Al-Si alloy

Abstract

High silicon aluminum alloy has broad applications in high power packaging parts and automobile lightweight. However, hard and brittle Si particles make the alloy surface easily to break during machining, resulting in serious surface defects. In this paper, a pulsed laser surface remelting non-resonant vibration assisted grinding method was proposed. The advantages of high instantaneous energy and quick cooling rate of pulsed laser are applied to form a remelting layer. The machinability of the alloy is improved by refining Si particles. The periodic separation of the workpiece-tool is used to reduce grinding forces and tool wear when abrasive particles cut the modified layer with higher hardness. The influence of remelting of the alloy induced by different power pulse laser on the material mechanical properties was revealed by laser irradiation experiments and indentation experiments. The influence mechanism of pulsed laser on the crystal structure and element distribution was simulated by molecular dynamics. The validity of the grinding method was confirmed by characterizing the grinding force, residual stress, tool wear, surface roughness and surface defect. The surface roughness of Al-27 wt. %Si decreased to 26 nm under the condition of 20 W power, 2 μm amplitude and 650 Hz frequency. The study reveals the deep mechanism of pulsed laser in laser assisted manufacturing and opens up a new research idea for the precise and low-damage processing of high silicon aluminum alloy.