超重力场反应连接制备TiB2-TiC/1Cr18Ni9Ti和TiB2-TiC/Ti-6Al-4V梯度复合材料

TiB_2-TiC/1Cr18Ni9Ti and TiB_2-TiC/Ti-6Al-4Vgraded composites achieved by reaction joining in high-gravity field

以1Cr18Ni9Ti、Ti-6Al-4V为金属基底,通过在B4C+Ti体系中引入CrO_3+Al铝热剂,调整反应体系绝热温度依次为3 193、3 282、3 290及3 473K,采用超重力场反应连接制备TiB_2-TiC/1Cr18Ni9Ti和TiB_2-TiC/Ti-6Al-4V梯度复合材料,发现随着反应绝热温度升高,陶瓷/金属界面区厚度不仅因金属熔深增加而增大,并且残存于界面上的Al_2O_3夹杂也随之增多。分别对B4C+Al体系与CrO_3+Al铝热剂进行配制、球磨活化、压制成坯并依次填料入坩埚后,发现残存于界面上的Al_2O_3夹杂完全消除,同时发现在TiB_2-TiC/1Cr18Ni9Ti界面上生成三维网络陶瓷/金属梯度复合结构,而在TiB_2-TiC/Ti-6Al-4V界面上形成跨尺度多层次梯度复合结构。

1Cr18Ni9Ti and Ti-6Al-4Vwere selected as the metal substrates,and CrO3＋Al thermit was introduced into B4C＋Ti primary system for adjusting the adiabatic temperature of reaction system as 3 193,3 282,3 290and3 473 K,TiB2-TiC/1Cr18Ni9 Ti and TiB2-TiC/Ti-6Al-4Vgraded composites were prepared by reaction joining in high-gravity field.Because increasing reaction adiabatic temperature brought about the increased melting depth of metal substrates,the intermediate between the ceramic and metal increased in thickness while Al2O3 inclusions at the interfacial areas inevitably increased.By changing the processing route,i.e.respectively preparing,ball-milling and compacting B4C＋Ti blends and CrO3＋Al thermit and subsequently filling them one by one into the crucibles,it is found that Al2O3 inclusions at the intermediates are removed completely,three-dimensional network ceramic/metal graded composite structure develope in the interface of TiB2-TiC/1Cr18Ni9 Ti,while in the interface of TiB2-TiC/Ti-6Al-4Vthere forms the multiscale and multilevel graded composite structure.