层厚对TiCN-VC/TiCN-TaC层状陶瓷微观组织和力学性能的影响

Effects of Layer Thickness on Microstructure and Mechanical Properties of TiCN-VC/TiCN-TaC Layered Ceramics

利用真空热压烧结技术和粉体叠层技术,在1450℃下制备了4种层厚的TiC_(0.7)N_(0.3)-VC/TiC_(0.7)N_(0.3)-TaC层状陶瓷,研究了层厚对其微观组织和力学性能的影响。结果表明:TiC_(0.7)N_(0.3)-VC层主要是由TiCN、(Ti,V,Mo)(C,N)固溶体,以及少量的Mo Ni4组成,TiC_(0.7)N_(0.3)-TaC层主要是由TiCN、(Ti,Ta,Mo)(C,N)固溶体,以及少量的Mo Ni4组成。随着层厚的增加,材料内部微观组织基本没有变化,晶粒的平均尺寸均在2μm左右。随着层厚从0.20 mm增加到0.32 mm,其相对密度和维氏硬度先增大后减小,抗弯强度的变化较小,层间的断裂韧度逐渐减小,而层面的断裂韧度基本保持不变。当层厚为0.28 mm时,材料的致密度较高,晶粒大小均匀,综合力学性能最佳,其硬度为20.9 GPa、抗弯强度为925.0 MPa、层间的断裂韧度为7.7 MPa·m^(1/2)。

Using vacuum hot pressing sintering technology and powder stacking technology,four kinds of TiC_(0.7)N_(0.3)-VC/TiC_(0.7)N_(0.3)-TaC layered ceramics with different layer thicknesses were prepared at 1450℃.The effects of layer thickness on the microstructure and mechanical properties were investigated.The results show that the TiC_(0.7)N_(0.3)-VC layer is mainly composed of TiCN,(Ti,V,Mo)(C,N)solid solution,and a small amount of MoNi_(4),and the TiC_(0.7)N_(0.3)-Ta C layer is mainly composed of TiCN,(Ti,Ta,Mo)(C,N)solid solution and a small amount of MoNi_(4).As the layer thickness increases,their microstructures are basically unchanged,and the average grain size is about 2μm.As the layer thickness increases from 0.20 mm to 0.32 mm,the relative density and Vickers hardness first increase and then decrease,the variation of flexural strength is smaller,and the interlaminar fracture toughness gradually decreases,while the fracture toughness of layer surfaces is basically unchanged.When the layer thickness is 0.28 mm,the ceramic has higher density,uniform grain size,and obtain excellent mechanical properties.Its Vickers hardness is 20.9 GPa,its flexural strength is 925.0 MPa,and its interlaminar fracture toughness is 7.7MPa·m^(1/2).