Quasi-static and dynamic hardening and fracture strain of A2-70
stainless steel under different temperatures
Abstract
In this paper, the behaviour of A2-70 stainless steel is investigated by
performing tensile tests on round specimens at different temperatures
under quasi-static and dynamic conditions. The relationship between
thermal softening and strain is firstly investigated, highlighting that
the variability of the necking strain under different temperatures is a
proof of such interaction. The competing effects of strain rate and
temperature in respectively delaying and anticipating the necking onset
are also quantified analytically, referring to multiplicative hardening
models with and without the coupling of strain and temperature. Then,
the comparison of necking strains from static and dynamic (Hopkinson
bar) tests at different temperatures is analysed, for understanding
which effect among thermal softening and dynamic stress amplification
prevails in anticipating/delaying the necking. Fracture strains and the
shapes of specimens at failure are finally related to the respective
strain rates and temperatures.