电场辅助Ti-Si连接碳/碳复合材料

Electric field assisted Ti-Si joining of carbon/carbon composites

为快速制备高温适用型碳/碳(C/C)复合材料接头,采用电场辅助热压烧结工艺,以Ti-Si对C/C复合材料进行原位反应连接。研究温度对接头微观结构和力学性能的影响,并对接头的失效过程进行分析。结果表明:连接温度为1 450℃、保温时间为5 min、加载压力为20 MPa时,连接所得接头的室温剪切强度为19.35(±2.29)MPa,比1 350℃时提高40%以上。原因在于:温度较低(1 350℃和1 400℃)时,Ti-Si与C/C母材反应有限,在连接区域难以形成连续、致密的界面结合;温度较高(1 450℃)时,Ti-Si与C/C母材反应充分,且往母材内部渗透较深,可以形成界面结合良好的连接区域,中间层厚度为10~30μm。但剧烈反应会损伤C/C母材的结构,最终导致虽然界面结合良好但接头依然从界面附近失效的结果。

To prepare high temperature applicable carbon/carbon(C/C) composite joints,an electric field assisted hot pressing sintering process was used to perform in-situ reactive bonding of C/C composites with. Ti-Si. Effects of temperature on the microstructure and mechanical properties of these joints were investigated,and the failure process of the joint was analyzed. The results show that the room temperature shear strength of the joint is19.35(± 2.29)MPa when the bonding temperature is 1 450 ℃,the holding time is 5 min and the loading pressure is 20 MPa,which is 40% higher than that at 1 350 ℃. The reason is that when the temperature is low(1 350 ℃ and 1 400 ℃),the reaction between Ti-Si and C/C base metal is limited,and it is difficult to form a continuous and dense interface bonding in the connection area. When the temperature is higher(1 450 ℃),Ti-Si reacts fully with the C/C base metal,and penetrates deeper into the base metal,forming a good interface bonding area,and the thickness of the intermediate layer is 10~30 μm. However,the severe reaction will damage the structure of the C/C base metal,and eventually lead to the failure of the joint near the interface although the interface is well bonded.