We have developed a unique electrical pulse-heated Kolsky Bar technique for measuring the flow stress of metals at heating rates of up to 6000 °C per second and strain rates up to 10^4 per second. Under these conditions, which are approaching those found in high speed machining, thermally activated microstructural processes such as grain growth, solid state phase transformation and dislocation annealing may be bypassed, leading to unusual non-equilibrium superheated states. Flow stresses may thus differ significantly from equilibrium high temperature conditions. This paper briefly describes our pulse-heated Kolsky bar technique and discusses recent results on an AISI 1075 pearlitic steel heated rapidly up to and beyond the austenite formation temperature.
Proceedings Title: DYMAT 2009
Conference Dates: September 7-17, 2009
Conference Location: Brussels, -1
Pub Type: Conferences
high strain rate, kolsky bar, pulse-heating, steel