高强度Cu-Ni-(Al)-Si合金的组织和性能

通过光学显微镜、维氏硬度计、双臂电桥、扫描电子显微镜、透射电子显微镜等测试手段对Cu-5.2Ni-1.2Si和Cu-5.2Ni-1.5Al-1.2Si合金的组织结构和性能进行了表征与测试。结果表明:2种合金的铸态组织均为发达的树枝晶组织,包括白亮的枝晶区、非平衡凝固相粒子及中间过渡区。其中枝晶为富Cu区,凝固相为富Ni和Si区,Al元素则比较均匀地分布在铸态组织中。峰值时效后,Cu-5.2Ni-1.5Al-1.2Si合金具有比Cu-5.2Ni-1.2Si合金更高的硬度。Al元素不但促进了Ni2Si的沉淀析出,还形成了Ni3Al沉淀相,从而大大提高合金强度。2种合金的时效早期均出现了有序化,峰时效时主要为沉淀析出强化,合金具有较好的抗过时效能力。

Microstructure and Properties of Superhigh Strength Cu-Ni-(Al)-Si Alloy

Microstructure and properties of the Cu-5.2Ni-1.2Si and Cu-5.2Ni-1.5Al-1.2Si alloy were studied by optical microscope, Vickers hardness tester, two-arm electricity bridge, scanning electron microscope and transmission electron microscope. Results show that the developed dendrite appears in the casting ingot, which can be divided into dendrite area, non-equilibrium precipitates and the middle transition region. The dendrite area is rich in Cu element, the precipitates are rich in Ni and Si elements, and the Al element is distributed in the ingot evenly. After the appropriate thermo-mechanical treatment, the hardness of Cu-5.2Ni-1.5Al-1.2Si alloy is higher than that of Cu-5.2Ni-1.2Si alloy, and Ni2Si precipitates contribute to the main strength. Al element promotes the Ni2Si precipitation process. A new phase of Ni3Al is formed, which also improves the strength of the alloy effectively. Ordering transformation appears in the early state of ageing treatment, and the high strength is attributed to the precipitation particles. The designed alloy exhibits good anti-over aged capability