T6热处理对SiC_p/Al复合材料高速铣削加工性的影响

Influences of T6 Heat Treatment on High-speed-milling Machinability of SiC_p/Al Composites

使用聚晶金刚石(PCD)刀具,在切削速度为1200m/min下对碳化硅颗粒增强铝基(SiCp/Al)复合材料进行铣削加工试验,研究SiCp/Al复合材料经T6热处理后对其高速铣削加工性的影响。结果表明:经T6热处理后,切削力/切削温度明显高于未热处理材料,切屑锯齿形明显,加工过程不稳定性增加,刀具承受冲击作用增大,导致PCD刀具发生较严重的崩刃、剥落、冲击裂纹等磨损形式,从而刀具使用寿命显著低于高速铣削未热处理材料。T6热处理材料高速铣削表面粗糙度Ra/Rz值一般低于未热处理材料,其加工表面变质层深度也显著低于未热处理材料,加工表面存在较少的坑洞、微裂纹、基体撕裂、基体涂覆等加工所致缺陷。

PCD tool was used to investigate the influences of heat treatment on the machinability when high--speed milling of SIC--particle--reinforced aluminum matrix composites at the cutting speed of 1200m/min. The results show that the cutting forces and the cutting temperature of T6 composite are higher than that of no heat treated material. The saw--toothed chip form is more evident for the T6 material. The above facts indicate that the cutting process of T6 materials is more unstable and that the PCD tool suffers from more cutting impact, which induces excessive chipping, peeling, cracks on the cutting tool. Therefore, the tool life when high speed milling the T6 composites will be much lower than that of the no heat treated materials. The results also show that the machining induces defects such as pits, micro cracks, matrix tearing and smearing etc. are much less for the T6 materials, which results in low surface roughness value and shallow hardened layer.