显微缩松对Ag-28Cu-0.75Ni合金性能影响研究

Effect of microporosity on properties of Ag-28Cu-0.75Ni alloy

分别采用水冷铜模铸造、石墨模铸造两种工艺获得具有不同显微缩松的Ag-28Cu-0.75Ni合金铸锭,通过模锻开坯、旋锻减径、热处理及拉拔等工艺对两种铸锭进行超细丝加工。研究不同铸造工艺下显微缩松对Ag-28Cu-0.75Ni合金超细丝加工、电学及力学性能的影响。结果表明,直径30 mm的Ag-28Cu-0.75Ni合金铸锭芯部分布有显微缩松,且水冷铜模铸造铸锭的显微缩松含量更高、尺寸更大;经过锻造加工后显微缩松呈现出“愈合”的趋势,但无法完全消除显微缩松;显微缩松含量高、尺寸大的Ag-28Cu-0.75Ni合金铸锭加工得到的丝材电阻率较高、抗拉强度较低。通过合理的热处理,能有效消除加工硬化、残余应力,两种铸锭均可拉拔加工至直径0.05 mm的超细丝。

Two Ag-28Cu-0.75Ni alloy ingots with different microporosity were prepared by water-cooled copper mold casting and graphite mold casting,the ultra-fine alloy wires were obtained through die forging billet,rotary forging for diameter reduction,heat treatment and drawing.The effects of microporosity of the alloys prepared by different casting methods on the processing,electrical properties and mechanical properties of Ag-28Cu-0.75Ni alloy ultra-fine wires were studied.The results showed that microporosity was distributed in the core of Ag-28Gu-0.75Ni alloy ingots within a diameter of 30 mm,and that the alloy prepared by water-cooled copper mold casting has high microporosity content and larger size.After forging,the microporosity porosity showed a“healing”trend,but it can’t be completely eliminated.Ag-28Cu-0.75Ni alloy wires with more and larger microporosity has high resistivity and low tensile strength.Through proper heat treatment,the work hardening and residual stress can be effectively eliminated.Both ingots can be drawn to 0.05 mm ultra-fine wires.