Ultra-low temperature grinding process and surface integrity of SiCp/Al material
摘要
ObjectivesAs a new-generation high-performance structural material, silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al) exhibit outstanding specific strength, wear resistance, and thermal stability, making them highly valuable in aerospace precision components, electronic packaging substrates, and other advanced manufacturing fields. However, common machining-induced damage issues such as matrix smearing and particle fragmentation severely compromise surface integrity and service performance. This study focuses on 20% SiCp/Al composites, systematically investigating the effects of process parameters on grinding force evolution, surface damage mechanisms, and surface integrity by comparing liquid nitrogen ultra-low temperature and room temperature air-cooling grinding conditions. The aim is to reveal the regulatory mechanisms of ultra-low temperature environments on composite machining performance and provide theoretical guidance for precision process optimization.MethodsGrinding experiments are conducted on 20% SiCp/Al composites using diamond grinding wheels under single-factor conditions. The ultra-low temperature grinding experiments are performed on a vertical machining center with internal liquid nitrogen jet cooling, while conventional room temperature air-cooling serves as the control group. Process parameters includes wheel speed 2.04 to 2.98 m/s, feed rate 50 to 200 mm/min, grinding depth 5 to 20 μm, and grinding width 6 mm. A dynamometer monitored normal and tangential grinding forces in real time. Surface roughness is measured via white light interferometry, residual stress measured via X-ray diffraction analysis, and microhardness measured via a microhardness tester. Surface and subsurface damage is characterized using scanning electron microscopy.Results(1) Under both cooling conditions, grinding forces decreases with increased wheel speed and increases linearly with feed rate and grinding depth. The ultra-low temperature environmen