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

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。

TiB2-TiC/1Cr18Ni9Ti and TiB2-TiC/Ti-6Al-4V graded composites achieved by reaction joining in high-gravity field

1Cr18Ni9Ti and Ti-6Al-4V were 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, 3 290 and 3 473 K, TiB₂-TiC/1Cr18Ni9Ti and TiB₂-TiC/Ti-6Al-4V graded 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/1Cr18Ni9Ti, while in the interface of TiB₂-TiC/Ti-6Al-4V there forms the multiscale and multilevel graded composite structure.