Fracture micromechanisms and plasticity of FeCrNiTi alloys in the temperature range 77-4.2 K

The tensile properties and fracture character of a series of FeCrNiTi alloys deformed under tensile stress in the temperature range 77-4.2 K have been investigated. Quantitative fractography with the use of panorama patterns of fracture surfaces and statistical analysis of structural elements revealed the major fracture mechanisms of alloys. The viscous mechanism of microvoid nucleation, growth and coalescence is the principal mechanism at all temperatures. Temperatures below 50 K led to quasi-viscous and quasi-brittle fracture components. The quantitative contribution of different mechanisms of crack propagation depends on temperature and alloying element content. The local plastic strains occurring in microvolumes during viscous fracture exceed the macroscopic plasticity of alloys by more than one order of magnitude.