Some data on the TiC-TiNi system's hard-alloy composite with high performance properties

Abstract

The data are provided on the composite material of the TiC-TiNi system with increased performance properties, which belong to the group of CM based on refractory titanium compounds called "tungsten-free hard alloys". The concept of a structural-energy transition from the perspective of thermodynamics is involved and developed. Based on this concept, the evolution of the structural-energy state of a composite material in the form of a model with two energy levels is considered. In the process of forming a composite mixture with a stable equilibrium structure, new stress-strain structures with an energy level of E1, which are unstable and have higher mechanical properties, arise. During sintering, the deformed structures with the energy level E1 pass into a more stable state with the energy level E2 due to the formation of energy-winning eutectic structures of the TiNi binding phase and the fine-grained dense structure of TiC carbides, which represent a steady metastable structure of the composite. It is established that depending on the volume concentration of the TiNi binding phase, the development of thermodynamic processes for forming the structure of a hard-alloy composite leads to the production of a final structure of the two different types and performance properties. It is shown that the critical concentration can be considered a volume concentration of 40% (vol). The resonant-acoustic method allowed to determine the visco-elastic characteristics (Young, shear, and compression moduli; Poisson's ratio), as well as their dependence on the concentration of the binding phase. The Young's modulus is theoretically calculated. It was found that the use of TiC-TiNi hard-alloy composite allows to increase the efficiency of the cutting tool and technological equipment by one and a half times compared to a tool made of the known tungsten-free alloys KNT-16, TN-(20, 30) and KTS.