High tungsten-tantalum alloy products after hot isostatic pressing in the preparation process of powder metallurgy high tungsten-tantalum alloy products, through a two-step heat treatment method, first use zirconium sponge as a deoxidizer to adsorb oxygen in high tungsten-tantalum alloy products, and then use high temperature vacuum heat treatment to further promote the solid solution oxygen and residual oxide volatilization in high tungsten-tantalum alloy products. Effectively reduce the oxygen content of high tungstan-tantalum alloy products, purify the grain boundary, combined with the effect of high temperature sintering, improve the grain boundary binding force, thus greatly improving the plasticity of the alloy, to solve the problem of oxygen enrichment in the process of hot isostatic pressing caused by high tungstan-tantalum alloy products, plastic drop sharply.
The above method of improving the plasticity of powder metallurgy high tungsten-tantalum alloy is characterized in that the specific process of the method is: After hot isostatic pressing, the high tungstan-tantalum alloy products are processed to remove the titanium or niobium envelope, then placed in a crucible and buried with zirconium sponge, and the whole product is placed in a vacuum furnace for a primary heat treatment. After the furnace temperature drops to room temperature, the sponge zirconium is removed, and the high tungstan-tantalum alloy products together with the crucible are placed in a vacuum furnace for a secondary heat treatment, and then cooled out. The system of the primary heat treatment is: holding heat for 1h ~ 3h at 1300℃ ~ 1450℃, and maintaining the vacuum degree of 5.0×10-1 ~ 5×10-3Pa during the heating, holding and cooling process of the primary heat treatment; The secondary heat treatment system is: heat preservation 2h ~ 4h at 2160℃ ~ 2200℃, and the vacuum degree is maintained 5.0×10-2 ~ 5×10-4Pa during the heating, heat preservation and cooling process of the secondary heat treatment. Tantalum and tantalum alloy begin to absorb oxygen above 400℃, even in the vacuum heat treatment of oxygen content will increase, oxygen in tantalum and tantalum alloy has the effect of solid solution strengthening, so that its hardness increases by 1 to 3 times, but it greatly reduces the plasticity of tantalum and tantalum alloy, therefore, tantalum and tantalum alloy solid solution of oxygen as a harmful element that damages plasticity, to minimize or remove. According to the situation, the invention creatively uses a two-step heat treatment process: First, the hot isostatic pressing high tungsten-tantalum alloy products after removal of the sheath are placed in the crucible and the sponge zirconium is used to bury them for a primary heat treatment under vacuum condition, and the temperature of the primary heat treatment is limited to 1300℃ ~ 1450℃.
