摘要
通过ＴｉＣ与Ｂ４Ｃ的化学反应，在Ｂ４Ｃ基体内原位生成ＴｉＢ２颗粒，获得的ＴｉＢ２颗粒粒径一般在３μｍ以下。其中加入２０ｖｏｌ％ＴｉＣ（对应的ＴｉＢ２为３５ｖｏｌ％）的复相陶瓷的断裂韧性值ＫＩＣ达６．３ＭＰａ·ｍ１／２，比单体Ｂ４Ｃ提高７５％，加入１０ｖｏｌ％ＴｉＣ（对应的ＴｉＢ２为１４ｖｏｌ％）的复相陶瓷的抗弯强度达到最大值６２０ＭＰａ，比单体Ｂ４Ｃ提高４０％。由Ｂ４Ｃ和ＴｉＢ２颗粒之间热膨胀系数不匹配产生残余应力而引起的裂纹偏转和微裂纹增韧是主要的增韧机理，反应生成的碳对材料的强度和显微硬度有不良影响。
Fine TiB_2 particles are produced in situ-B_4C through reaction of B_4C + 2TiC = 2TiB2+3C and B4C-based composites are prepared by hot-press process at 2050℃. The composite derived from B4C-20vol% TiC has a peak KIC value of 6. 3MPa· m1/2,which is higher than that of monolithic B,C by 75%' The material resulting from B4C-10vol%TiC enjoys a maximal bending strenght of 620MPa,which is 40% higher than that of monolithic B.c' The crack denection and microcrack toughening caused by the residual stress resulting from the difference in thermal expansion coefficient between B.C and TiB2 are the main toughening mechanisms. The carbon derived from the reaction is one reason for the decrease in bending strength and Vickers hardness.
出处
《粉末冶金技术》
CSCD
北大核心
1996年第3期168-174,共7页
Powder Metallurgy Technology
