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研究了对压铸SiCw/Al复合材料进行大应变变形及回复和再结晶的行为。对复合材料的塑性变形研究表明,挤压温度过高导致复合材料表面产生宏观裂纹;包覆挤压可有效地消除表面宏观裂纹;挤压比越大,晶须的定向排列和折断程度越大;提高挤压温度及采用流线型模具可减小晶须折断程度,并可提高复合材料的纵向抗拉强度;提高挤压比不能单调地增大纵向抗拉强度。挤压后T6处理可大幅度提高复合材料的强度。 对复合材料压缩变形时晶须行为研究表明,基体金属不均匀流动导致晶须的转动,晶须转动受晶须排列和晶须与基体的约束影响;晶须的折断是由于晶须与基体变形不协调的结果。 对复合材料的再结晶研究表明,冷变形复合材料基体为形变亚晶,晶内位错呈胞状结构。冷轧15％SiCw/L3复合材料的再结晶起始温度为200℃。高体积分数晶须的存在促进了回复,导致连续再结晶和不连续再结晶同时发生。晶须端部和侧面是有利的非连续再结晶形核场所。与基体金属相比,复合材料的形变织构和再结晶织构被弱化,主要织构组分强度也与基体金属不同。溶质原子使冷变形复合材料的再结晶过程延迟。时效析出相与晶须促进复合材料退火时发生连续再结晶。
The behavior of large deformation, recovery and recrystallization of die-cast SiCw / Al composites was studied. The plastic deformation of the composites shows that the extrusion temperature is too high to cause macroscopic cracks on the surface of the composites. The extrusion coating can effectively eliminate the macroscopic cracks on the surface of the composites. The greater the extrusion ratio, the greater the orientation and fracture of the whiskers ; To improve the extrusion temperature and the use of streamline mold can reduce the degree of whisker fracture, and can improve the longitudinal tensile strength of the composite material; improve the extrusion ratio can not monotonically increase the longitudinal tensile strength. Extrusion T6 treatment can greatly improve the strength of the composite material. The whisker behavior of the composites under compressive deformation shows that the non-uniform flow of the matrix metal leads to the rotation of the whiskers, and the whisker rotation is affected by the whisker alignment and the confinement of the whiskers and the matrix. The breakage of the whiskers is caused by the deformation of the whiskers and the matrix Uncoordinated result. The study on the recrystallization of the composite shows that the cold deformed composite matrix is deformed subgrain, and the intragranular dislocation is in a cellular structure. The recrystallization onset temperature of cold-rolled 15% SiCw / L3 composites was 200 ℃. The presence of high volume fraction whiskers promotes recovery, resulting in simultaneous recrystallization and discontinuous recrystallization. Whisker ends and sides are favorable places for discontinuous recrystallization nucleation. Compared with the base metal, the deformation texture and recrystallization texture of the composite material are weakened, and the strength of the main texture component is also different from that of the base metal. Solute atoms delay the recrystallization of the cold-deformed composite. Continuous recrystallization occurs during aging of the precipitated phase and the whisker-promoted composite.