SiCp/Al复合材料磨削去除形式及表面损伤研究

Research on Grinding Removal Form and Surface Damage of SiCp/Al Composites

摘要: 目的：展开SiCp/Al复合材料磨削加工中SiC颗粒去除机理以及磨削加工表面完整性的分析。方法：设计了材料数值模型与单因素磨削实验，以J-C本构模型和颗粒断裂准则作为材料损伤依据，对20%vol SiCp/Al进行切削仿真数值模拟，从磨削力、材料内部应力变化及分布等研究SiC颗粒与磨粒相对位置对其去除机理的影响，采用干式逆磨在CarverS600A机床上展开磨削试验，分析不同工艺参数对表面粗糙度的影响，分析典型表面缺陷及成因。结果：磨粒切削SiC颗粒时的磨削力是磨削Al基体的5~7倍，材料内部应力集中现象多发生于SiC颗粒与Al基体界面，SiC颗粒被切削深度增大，小尺寸颗粒易发生脱粘去除，大尺寸颗粒易发生断裂破碎，当砂轮线速度由4.7 m/s增大到9.4 m/s时，沿磨削方向表和垂直磨削方向的粗糙度均呈现下降趋势，当磨削深度由3 μm增大到12 μm或工件速度由50 mm/min增大到200 mm/min，沿磨削方向表和垂直磨削方向的粗糙度均呈现增大趋势。结论：SiC颗粒的去除方式为断裂破碎、脱粘拔出、解离破碎为主，这是造成表面完整性差的主要原因，减小磨削深度增大砂轮线速度可显著减少表面缺陷。

Abstract: Objective: To develop the analysis of SiC particle removal mechanism and surface integrity of grinding process in SiCp/Al composite materials. Methods: A numerical material model and sin-gle-factor grinding experiments were designed to simulate the cutting of 20%vol SiCp/Al based on the J-C intrinsic structure model and the particle fracture criterion. The grinding test was carried out on a CarverS600A machine using dry reverse grinding to analyze the effect of different process parameters on the surface roughness and to analyze the typical surface defects and their causes. Result: The grinding force when the grinding grain cuts SiC particles is 5~7 times of grinding Al substrate, and the material The internal stress concentration phenomenon occurred mostly at the interface between SiC particles and Al substrate, the depth of SiC particles cut increased, the small size particles were easy to be debonded and removed, and the large size particles were easy to be fractured and broken, when the grinding wheel linear speed increased from 4.7 m/s to 9.4 m/s, the roughness along the grinding direction table and vertical grinding direction showed a decreasing trend, when the grinding depth increased from 3 μm to 12 μm or the workpiece speed increased from 50 mm/min to 200 mm/min, the roughness along the grinding direction table and vertical grinding direction showed a decreasing trend. Conclusion: The removal of SiC particles was mainly by fracture crushing, debonding extraction and dissociation crushing, which were the main reasons for the poor surface integrity, and reducing the grinding depth and increasing the grinding wheel linear speed could significantly reduce the surface defects.