铸造工艺对ZL114A铝合金铸件组织和性能的影响

Effect Of Casting Process On The Microstructure And Properties Of ZL114A Aluminium Alloy Castings

  • 摘要: 使用低压铸造工艺和差压铸造工艺对比研究了某ZL114A铸件的组织和性能差异。结果表明,两种铸造工艺下合金铸态组织主要由α-Al基体、共晶硅相组成,经过T6处理后,铸态中的粗大共晶相转变为细小的球状。差压铸造工艺下合金的抗拉强度、屈服强度和伸长率平均值分别为345MPa、306MPa、5.3%,相较于低压铸造工艺分别提升了6.2%、9.3%、17.8%。这是由于差压铸造工艺在金属液凝固过程中可以提供更好的补缩能力,合金组织更为致密,合金的晶粒细化效果好,且组织中第二相分布更弥散、均匀,第二相强化效果好。两种方式下合金的断裂机制均为韧-脆混合型,但差压铸造工艺下合金塑性特征更明显。

     

    Abstract: The differences in the microstructure and properties of a ZL114A casting were comparatively investigated using a low pressure casting process and a differential pressure casting process. The results showed that the as-cast microstructure of the alloy under the two casting processes mainly consisted of α-Al matrix, eutectic silicon phase, and the coarse eutectic phase in the as-cast state was transformed into fine spherical shape after T6 treatment. The average values of tensile strength, yield strength and elongation of the alloy under the differential pressure casting process are 345 MPa, 306 MPa and 5.3%, respectively, which are 6.2%, 9.3% and 17.8% higher than those of the low pressure casting process. This is due to the differential pressure casting process in the liquid metal solidification process can provide better shrinkage capacity, the alloy microstructure is more dense, the alloy grain refinement effect is good, and the second phase distribution in the microstructure is more diffuse and uniform, the second phase strengthening effect is good. The fracture mechanism of the alloy in both ways is a mixed tough-brittle type, but the plasticity characteristics of the alloy are more obvious under the differential pressure casting process.

     

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