压力对ADC12铝合金超低速压铸件组织及力学性能的影响

采用光学显微镜、扫描电镜、X射线衍射和能谱等显微分析技术,结合力学性能检测,研究超低速压铸条件下压力对ADC12铝合金铸件组织及力学性能的影响。试验结果表明,在超低速试验条件下,持压时间越长、增压延时时间越短,铸件性能越好;铸造压力导致初生α-相形态发生变化,但铸造压力有最佳值,压力较小时,增大铸造压力可使α-相细化,铸件性能升高,过大的铸造压力将导致α-相粗大,使铸件性能下降;在无增压条件下,仅采用较大的压射压力也可使α-相组织细小,获得较好的力学性能。

Effects of Casting Pressure on Microstructure and Mechanical Properties of Super Slow Speed Die Castings of ADC12 Aluminum Alloy

The microstructure of super slow speed(SSS)die castings of ADC12 aluminum alloy were analyzed by optical microscope, SEM, X-ray diffusion and energy spectrum and the influences of casting pressure on microstructure and mechanical properties were investigated. The results show that in a SSS die casting process, the longer the pressure intensification time and the shorter the time lag before pressure intensification, the better the die casting properties; The primary-phase in the cast structure could be changed by the casting pressure and there exists an optimum casting pressure for the microstructure and mechanical properties. When the casting pressure is small, increasing casting pressure leads to finer primary-phase and higher mechanical properties, but too large casting pressure leads to larger primary-phase and decrease of mechanical properties. Better properties can also be obtained under a high injection pressure without pressure intensification.