退火温度对冷轧气相沉积高纯钨再结晶行为的影响

Recrystallization behavior of chemical vapor deposited high purity tungsten after cold-rolling was studied by using annealing experiments at different temperatures. The results show that layered heterostructure is formed in the cold-rolled tungsten, which improves the strain hardening rate of the material, thereby improving the plasticity. After cold rolling, the ductile-brittle transition temperature is reduced to below 200℃, and the hardness is increased from 402 HV0.2 in deposited state to 547 HV0.2. After high temperature annealing, the cold-rolled tungsten recrystallizes at 1100℃, and the recrystallization temperature is reduced by 880℃ compared with the deposited tungsten. This is because the storage energy of the material is increased due to low-temperature plastic deformation, and the recrystallization driving force is increased, so the recrystallization temperature decreases. As the annealing temperature increases, the layered heterostructure gradually disappears due to the increase of grain size, the hardness rapidly decreases to 370 HV0.2 in the fully recrystallized state, and the yield strength gradually decreases from 1224 MPa in the cold-rolled state to 558 MPa after annealing at 1800℃, but the ductile-brittle transition temperature remains below 200℃.