Surface Damage Formation Mechanism of SiCp/Al Composites Based on 2D Cutting
The precision machining of silicon carbide particle reinforced aluminum matrix (SiCp/Al) composite with high surface integrity of low damage is a key challenge to ensure the components performance in service. However, due to the different mechanical properties of Al matrix and SiC reinforced phase, the surface damage formation of SiCp/Al composites varies markedly compared with homogeneous metallic materials. In order to investigate the surface damage formation mechanism of SiCp/Al composites, a 2D cutting simulation and experimental test are conducted in the study.Firstly, the cutting simulation model of SiCp/Al composite including Al matrix, SiC reinforced particles and interfacial properties was established by ABAQUS software, in which the volume fraction of SiC was 20％ and the cutting tool was rigid with 10° front angle and 5° back angle. The 2D cutting simulation was conducted at a series of cutting depth and cutting speed, by observing the material mechanical behavior in the process when the tool tip acted on different parts of SiC particles. Next, the ductile-brittle coexistence material removal mechanism and damage mechanism were analyzed.Then, the experimental 2D cutting platform was built by applying a high-speed linear motor. The corresponding experiments were conducted at cutting depths of 0.01, 0.02 and 0.03 mm and cutting speed of 2.5, 3.1 and 3.7 m/s. The microscopic morphology of the machined surface was observed with a scanning electron microscope (JSM-IT500HR) to analyze the surface damage in cutting process. The roughness Sa of the machined surface was measured with a white light interferometer (Npflex) to observe the surface morphology under different process parameters.Finally, through 2D cutting simulation analysis and high-speed 2D cutting verification, the mapping relationship of process conditions-removal mechanism-damage forms was obtained. The tool tip action on SiC particles largely determined the form of surface damage. When the tool tip acted on the upper of the SiC particles, the machined surface mainly produced damage such as particle crushing and cracking. When the tool tip acted on the middle of the SiC particles, the machined surface mainly produced particle crushing, cracking and cratering. When the tool tip acted on the bottom of the SiC particles, the machined surface mainly produced surface cratering.Furthermore, the effect of cutting parameters on surface quality was compared to obtain high-performance surface precision machining technology. With the cutting speed increasing to 3.7 m/s, the strain rate reinforcement effect of the Al matrix will make the holding force of Al matrix increase, the SiC particle fragmentation is significantly reduced, and the surface quality of the workpiece is improved. When the cutting depth increases to 0.03 mm, due to the failure areas of the SiC particle interface occurring, more particles are pulled out, leading to poor processing quality. Therefore, increasing the cutting speed and decreasing the cutting depth are beneficial to improving the surface quality, which can achieve long life and high reliability of SiCp/Al composite parts.
SiCp/Al compositeshigh-speed linear motorcutting simulationsurface damageremoval mechanismsurface quality
万方数据
维普
