Compaction and strengthening of ceramic-metallic materials with quadruple solid solutions of metal phases during plasma-spark sintering

Abstract

The article shows the effect of mixtures of metal powders Ti, Nb, Cr, Zr, Ti and Mo, Cr, V as well as Mo, Nb, Cr, Ta during spark plasma sintering of compositions at pressing loading 70 MPa in the range 1200-1600 ^oC on the phase composition, microstructure, grains sizes of crystalline phases, relative density, linear shrinkage, physical-mechanical properties, linear correlation, values of standart deviations of modulus of elasticity and fracture toughness of mullite-(Ti,Ta) (C,N)-B₄C-c-BN samples. Synthesized powders of TiC, TiN, B₄C, h-BN are characterisized by different intensity of crystallization of TiC, TiN, B₄C, h-BN phases, respectively. Sintered by spark plasma method solid solution of (Ti,Ta)(C,N) at 1500 ^oC shows intensive crystallization of (Ti,Ta)(C,N) phase, crystalline, uniform and densely sintered microstructure. Sintered samples with the mixtures of metal powders show similar mullitization, crystallization of (Ti,Ta)(C,N), B₄C, c-BN phases with different evolution of crystalline β-Ti,Nb,Cr,Zr, β-Ti,Mo,Cr,V β-Mo,Nb,Cr,Ta phases in the range 1200-1600 ^oC. Microstructures of sintered samples are crystalline, different uniform and variously densely sintered. The samples with the mixtures of metal powders form variously dispersed grains compositions of crystalline phases in the range 1200-1600 ^oC, different uniformity, density, path and width of boundary layers of solid solution of metallic phases, different particles packing of non-oxide and solid solution of metallic phases, have different path and width of propagating microcracks at the boundaries of particles of ceramic and solid solution of metallic phases at 1300 and 1500 ^oC, across the boundary layers of solid solutions of metallic phases at 1500 ^oC. This different effects the ingrowth and the values of physical-mechanical properties, the resistance to the cracking, the linear correlation, the values of standart deviations of modulus of elasticity and fracture toughness in the range 1200-1600 ^oC. Ill. 20. Ref. 18. Tab. 3.