表面纳米化Zr-4合金组织和性能热稳定性研究

Thermal Stabilities of Microstructures and Properties of Surface Nanocrystallized Zr-4 Alloy

采用表面机械研磨法(SMAT)对Zr-4合金进行处理,在其表面制备出纳米结构表层,并在不同温度下对其进行退火。利用偏光显微镜、X射线衍射仪、透射电镜、显微硬度计和电化学测量仪等分析手段,研究了SMAT处理Zr-4合金经不同温度退火后,其纳米表层组织、硬度的热稳定性,以及退火对耐腐蚀性能的影响。结果表明,SMAT处理Zr-4合金经低于350℃退火,其表层纳米晶组织、晶粒尺寸、显微硬度具有一定的热稳定性;Zr-4合金经SMAT处理实现表面纳米化后,其在1mol/LH2SO4溶液中的耐腐蚀性能降低,进一步对其在低于350℃进行退火,其耐腐蚀性能得到改善,且退火后的耐腐蚀性能要优于原始未经SMAT处理的Zr-4合金。

Nanostructured surface layer was synthesized on Zr-4 alloy surface by surface mechanical attrition treatment (SMAT), and then the alloy was annealed at different temperatures in vacuum. The effects of the annealing temperature on the thermal stabilities of microstructure and hardness, and the effect of annealing on corrosion resistance were investigated by means of optical microscope, X-ray diffraction, the transmission electron microscope, microhardness test and electrochemical testing. The results show that when the annealing temperature is below 350 degrees C, the microstructure, grain size and microhardness of surface nanocrystallized Zr-4 alloy have good thermal stability. The corrosion resistance in 1 mol/L H2SO4 solution for the alloy only after SMAT is decreased. However, after further annealing below 350 degrees C, its corrosion resistance is improved, which is better than that of Zr-4 alloy without SMAT treatment.