Zr对超重力场凝固Al-Ni-Co合金组织和力学性能影响

Effects of Zr on the Microstructure and Mechanical Properties of Al-Ni-Co Alloys by Super-gravity Field Solidification

采用超重力场凝固技术制备了不同Zr含量的Al-2.5Ni-0.1Co合金,研究了Zr含量对铸态和直接时效态合金显微组织和高温力学性能的影响。结果表明,Zr固溶于α-Al中并细化了合金的共晶团结构,其固溶效果和细化效果提升了铸态合金的显微硬度。当Zr含量为0.1%时,合金硬度(HV)达到峰值,约为65,Zr含量超过0.3%后,会形成富Zr相。直接时效后,Al-Ni-Co-Zr合金中析出二次Al_(3)Zr相,改善了合金硬度和高温力学性能,Zr含量为0.3%时,合金硬度(HV)最高约为87,300℃下抗拉强度、屈服强度和伸长率分别达到93.2 MPa、62.5 MPa和25.4%。

Al-2.5 Ni-0.1 Co alloys with different Zr contents were prepared by super-gravity field solidification technology, and the effects of Zr contents on the microstructure and high-temperature mechanical properties of as-cast and direct aged alloys were investigated. The results indicate that Zr is dissolved in α-Al and refines the eutectic colony structure of the alloys, and the microhardness of the as-cast alloys is increased by the effect of solid solution and refinement. With Zr content of 0.1%, the hardness of the alloy reaches a peak of about 65 HV, and the Zr-rich phase is formed when Zr content is over 0.3%. After direct aging, the secondary Al_(3)Zr phase is precipitated in the Al-Ni-Co-Zr alloy, improving the hardness and high-temperature mechanical properties of the alloy. When Zr content is 0.3%, the hardness of the alloy reaches up to about 87 HV, where the high-temperature tensile strength, yield strength and elongation of the Al-Ni-Co alloy at 300 ℃ reach 93.2 MPa, 62.5 MPa and 25.4%, respectively.