三元层状陶瓷Ti-Al-C、Ti3SiC2的连接以及层状材料的制备和性能

IMR OpenIR

	三元层状陶瓷Ti-Al-C、Ti3SiC2的连接以及层状材料的制备和性能
	李爱君
学位类型	博士
导师	周延春
	2011
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	Ti-al-c Ti3sic2 连接层状材料韧性形变能力非灾难性破坏 Ti-al-c Ti3sic2
摘要	"（一）Ti-Al-C体系（Ti2AlC、Ti3AlC2）以及Ti3SiC2的连接。 1. 在1400oC、120 min氩气气氛的连接条件下实现了对Ti-Al-C陶瓷强的连接。连接的机理主要是由于在低氧压的氩气气氛下Ti2AlC和Ti3AlC2基体中的Al发生选择性氧化从而在连接界面处形成连续致密且与基体结合良好的Al2O3层。得到的Ti-Al-C连接体的室温弯曲强度可达到基体材料的~90%，而且这种高的连接强度可保持到1000oC的高温。 2. 利用Cu或者Zr膜作为连接反应层可以在较低温度下实现对Ti3SiC2的连接，连接温度分别为950oC和1100oC。连接机制为：Si原子从Ti3SiC2基体中扩散出来进入溅射的Cu或Zr膜中并与之发生反应，在界面处生成与基体结合良好的Cu3Si或者Zr-Si化合物层。Ti3SiC2/Cu/Ti3SiC2接头的强度可以高达238 MPa，为基体强度的68%。（二）平板状Ti-Al-C/Al2O3层状复合材料和圆柱状Ti2AlC/graphite多层复合材料的制备和表征。 1. 基于在低氧分压氛围中1300oC条件下得到的Ti-Al-C连接体具有弱的连接界面层的原理，制备出Ti-Al-C/Al2O3层状复合材料。这种层状复合材料由原位生成的弱的Al2O3界面层连接的Ti-Al-C薄片层组成。断裂韧性测试过程中发现弱的Al2O3界面层可以使裂纹发生偏转，从而避免了层状材料的灾难性破坏，同时断裂韧性和断裂功较单一陶瓷也有较大的提高。 2. 为了改善Ti2AlC陶瓷在压缩过程中的脆性，仿照树的软硬相间的层状结构，成功的将超软的石墨层和弱的Ti2AlC界面结合层引入到单一Ti2AlC陶瓷中，从而制备出Ti2AlC/graphite圆柱状多层复合材料。压缩实验的结果表明，Ti2AlC/graphite圆柱状多层复合材料中引入的弱的界面层可以起到裂纹偏转的作用，从而阻止了断裂过程中灾难性破坏的发生，而且材料的形变能力也得到了提高，几乎是Ti2AlC单一陶瓷的两倍。由于弱的界面结合层与Ti2AlC硬质层之间良好的界面结合力，Ti2AlC/graphite圆柱状多层复合材料的压缩强度可以达到348 MPa，为Ti2AlC单一陶瓷的60%。"
其他摘要	"1. Joining of Ti-Al-C system (Ti2AlC and Ti3AlC2) and Ti3SiC2 (1) Strong Ti-Al-C joints can be achieved at 1400oC for 120 min in an argon atmosphere. The mechanism of the bonding is attributed to the preferential oxidation of Al atoms in the titanium aluminum carbides at low oxygen partial pressure, which leads to the formation of a continuous and adherent Al2O3 layer. Flexural strength of joints achieved at 1400oC is about 90% of the substrates, and the high flexural strength can be retained up to 1000oC. (2) Ti3SiC2 joining has been successfully achieved by depositing a thin Cu or Zr layer on it and heat treating at relatively low temperature of 950oC or 1100oC, respectively. The mechanism of bonding is attributed to the formation of a continuous and adherent Cu3Si or Zr-silicide layer at the joint interface through the outward diffusion of Si atoms from the Ti3SiC2 substrate into the deposited Cu or Zr layer. 4-point bending strength of Ti3SiC2/Cu/Ti3SiC2 joints reaches a value of 238 MPa, which is 68% of the Ti3SiC2 substrate. 2. Fabrication and characteristics of Ti-Al-C/Al2O3 laminated composites and cylindrical Ti2AlC/graphite layered composite (1) Based on the weak joint interface of Ti-Al-C joints achieved at 1300oC, we successfully fabricate the laminated Ti-Al-C/Al2O3 composites through heat treatment these ceramics at 1300oC and low oxygen partial pressure. The laminated composites consist of 0.5 mm thick layers of Ti-Al-C joined together by the in situ formed Al2O3 interlayers. It is shown that the weak Al2O3 interlayers can deflect cracks preventing catastrophic failure whilst raising the fracture toughness and work of fracture substantially. (2) Based on a biological analogue, a novel Ti2AlC/graphite layered composite with improved deformation capacity and noncatastrophic failure mode have been realized by introducing a soft graphite center and weak cracks-deflection Ti2AlC interlayers into the monolithic Ti2AlC ceramic. During the compressive test, the weak Ti2AlC interlayers can deflect cracks preventing catastrophic failure, and the strain of the layered composite is about twice of that for the monolithic Ti2AlC ceramic. Furthermore, due to the good adhesion between the interlayers and Ti2AlC hard-layers the compressive strength of the Ti2AlC/graphite layered composite is 348 MPa, which is 60% of the monolithic Ti2AlC ceramic."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64285
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	李爱君. 三元层状陶瓷Ti-Al-C、Ti3SiC2的连接以及层状材料的制备和性能[D]. 北京. 中国科学院金属研究所,2011.