High-temperature stability of TiAlN/TiB_2 multilayers grown on Al_2O_3 substrates using IBAD

摘要

TiAlN/TiB_2 multilayers which have various modulation ratios (t_(TiAlN):t_(TiB2)) ranging from 1:6 to 18:1 were synthesized on Al_2O_3(111) substrate by ion beam assistant deposition (IBAD). The effects of annealing on the mechanical and structural properties of the multilayers were investigated using X-ray diffractometry (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Nanoindenter (CSM instruments). It was found that the hardness for all multilayers was higher than TiAlN or TiB_2 monolayer and the highest hardness of 43GPa was attained at t_(TiAlN):t_(TiB2)=16:1. The multilayers show the polycrystallines of TiAlN(111) and (220) textures. The thermal stability characteristics of the multilayers were studied in vacuum furnace for 30min at temperatures of 500 and 700°C. Compared with as-deposited multilayers, the annealed multilayers displayed a stable hardness and elastic modulus and an increased fracture resistance. It was found that the multilayers showed good thermal stability.