Ti添加量对B4C-Ti复合陶瓷力学性能的影响

Effect of Ti doping on the Mechanical Properties of B4C Composite Ceramics

摘要:

本文采用热压烧结在1680℃下制备得到了(100-x)B₄C-xTi(质量百分比,%)陶瓷,并研究了Ti(x=0~40)添加量对B₄C陶瓷微观形貌及力学性能的影响。结果表明：Ti元素可以促进B₄C陶瓷的烧结,其相对密度随Ti含量增加先增大后趋于稳定,当Ti添加量达到40%时,样品相对密度约为99.5%；XRD结果表明,样品中除B₄C和未反应的Ti之外,还有TiC和TiB₂相出现,且随Ti含量增加,两者的衍射峰逐渐增强；随Ti添加量增加,样品的抗弯强度、硬度以及断裂韧性均增大,在添加量为40%时,分别达到481MPa、828Kgf.mm_-2、18.55MPa.mm_1/2。分析其原因认为,由于Ti与B₄C发生界面反应,在界面处生成TiC和TiB₂相过渡层,联结了B₄C基体与Ti,起到了桥联增韧的作用,使材料的力学性能得到改善。

关键词:界面结合;增强相;桥联增韧;阻断效应

Abstract:

In paper, it prepared the (100-x)B4C-xTi(wt.%) ceramic that through the hot press sintering in 1680℃, the effect of Ti to the microstructure and the mechanical properties of B₄C ceramic is studied. The results showed: it promoted the sintering of B₄C ceramic through Ti doping, the relative density would increase firstly, then it tends to increase slowly down. The relative density of the sample is 99.5%, when Ti doping get up to 40wt.%. The XRD result in the sample, in addition to the B₄C and unreacted Ti besides, there are TiB₂ and TiC phase,and with the increasing Ti content, the diffraction peaks of those two phase gradually increased; With the addition of Ti, bending strength, hardness and fracture toughness of samples increased, the doping amount was 40wt.%, respectively, up to 481±24MPa, 828±41Kgf.mm_-2, 18.55±0.9MPa.mm_1/2. It analysis that because Ti interface reaction with B₄C, generated at the interfaces of TiC and TiB₂ phase transition layer, connecting the B₄C substrate and Ti, have played an important role in bridging toughening, make the material mechanical performance is improved.

Key words:Interface bonding; Reinforced phase; Bridging toughening; Blocking effect