Preparation method of Al2O3 dispersion strengthened copper

Abstract

The invention provides a preparation method of Al2O3 dispersion strengthened copper. The preparation method comprises charcoal reduction preparation of Al2O3-containing copper powder, surface activation pretreatment on the Al2O3-containing copper powder, copper powder filling and coiling, isostatic pressing treatment on the coiled materials, reduction sintering, dense sintering, cooling, primary rotary swaging processing, Al2O3 alpha-phase crystal solid solution heat treatment and copper recrystallization heat treatment, and secondary rotary swaging processing. The preparation method has the advantages of high performance indexes, good stability, low energy consumption, less investment, high yield and large unit heavy.

Description

technical field [0001] The invention relates to the field of metal materials, in particular to a method for preparing aluminum oxide dispersion strengthened copper. Background technique [0002] Dispersion strengthened copper alloy (DispersionStrengthened Copper, referred to as DSC) is a copper-based material with excellent comprehensive physical and mechanical properties. Low thermal expansion coefficient, high dimensional stability and other comprehensive properties. The yield strength and tensile strength of dispersion strengthened copper are high, and even after annealing, most of the yield strength is still retained. Annealing can improve the ductility of copper alloys, but due to the high yield strength retention rate of dispersion strengthened copper, in high conductivity copper alloys , the work-hardened dispersion-strengthened copper has the highest yield strength. Dispersion-strengthened copper has strength comparable to many steels, yet conducts similarly to cop...

AI Technical Summary

Problems solved by technology

[0006] 1) High energy consumption, high cost, and unstable quality: due to the need for multiple hot processing, the energy consumption is high; at the same time, during hot extrusion, especially the first hot extrusion, the inner and outer layers of the billet bar are delaminated, resulting in cracks, resulting in low yield and low weight of a single finished product; at the same time, this method requires a large investment in production equipment and is difficult to widely promote

[0007] Taking the process of a nonferrous metal research institute in Beijing and a copper processing enterprise in Luoyang as examples, the method is: use cold isostatic pressing to make a short thick ingot with a maximum diameter of 220mm-230mm, a length of 250-350mm, and a weight of 100Kg. The billet extruded to a diameter of 90mm-60mm on a hot extrusion machine with an extrusion force of 2800-3200 tons, due to the influence of the extrusion force of the hot extrusion machine and the performance of the hot working die, the extrusion ratio should not be too large. Therefore, the ideal weight of the first extrusion billet is about 70Kg, and the ideal yield is 70%. In fact, due to the inconsistent extrusion deformation speed of the copper-aluminum alloy powder in the extrusion barrel, the billet is prone to internal and external delamination and shrinkage. , cracking and other defects, leading to scrapping and more grinding, resulting in the uncertainty of the length of the process cutting head and tail, so the material yield of the billet that can actually be transferred to the next process is only about 50%; It is difficult to cold process to a smaller finished product specification (generally less than 20mm in diameter), so the above-mentioned billet with a diameter of 90mm-60mm is cut to length to a small ingot with a diameter of 90mm-60mm, a length of about 200mm, and a single weight of about 10Kg; After heating to about 880°C, perform secondary extrusion on an extruder with an extrusion force of 600-800 tons. The weight of the final finished rod is less than 8Kg, and the final comprehensive yield is less than 35%.

[0008] 2) Low product quality: It is difficult to control the impurity oxygen content in the product dispersion-strengthened copper rod, and the average impurity oxygen content is > 150ppm, which cannot meet the raw material requirements for making electric vacuum components

Because the above-mentioned process must heat the powder isostatic ingot at high temperature before hot extrusion, although certain protective measures can be taken, it is difficult to avoid the high oxygen content of the material due to the high temperature oxidation of the powder isostatic ingot by oxygen in the air, especially There are a large number of microporous gaps in the powder isostatic pressing ingot microscopically, which causes the oxygen content to gradually increase from the inside to the outside along the radial direction of the ingot, and the oxygen infiltrated after extrusion remains in the inner matrix and cannot be eliminated, resulting in low product quality and poor performance

Images