STRUCTURAL AND STRENGTH PROPERTIES OF POROUS TiNi-BASE ALLOYS OBTAINED BY SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS AND DIFFUSION SINTERING

摘要

The structural features and physical-mechanical properties of porous TiNi-base materials obtained by self-propagating high-temperature synthesis and diffusion sintering have been studied. The physical-mechanical characteristics of the materials are shown to be determined by the special features inherent in the formation of their micro-and macrostructure. The ultimate strength and failure strain are found to depend on the porosity, pore and interporous bridge size and distribution, and phase-chemical composition of the materials under consideration. The strength properties of the sintered material are twice as high as those of its synthesized cousin. This is due to the macrostructural uniformity, less-pronounced phase-chemical nonuniformity, and precipitation hardening of the TiNi-base matrix by introducing a fine dispersion of TiNi3 particles. An analysis of the fracture surface patterns has revealed tough-brittle fracture of the materials.