Impacts of warm equal-channel angular pressing on microstructure and mechanical properties of granular pearlitic steel

Abstract Equal-channel angular pressing (ECAP) of granular pearlite high-carbon steel at 650 °C via the Bc route is thoroughly investigated. Together with microstructural evolution investigated through scanning and transmission electron microscopies, microtensile and microhardness testing are conducted for their mechanical properties. After four passes of warm deformation, the formed ultra-microduplex structure is found to contain both ferrite grains of size ≈0.45 μm and cementite particles with the diameter of ≈0.3 μm. The corresponding microhardness and tensile strength are observed to increase first, followed by a decrement with the number of deformations passes. Meanwhile, yield strength and yield ratio increase with the ECAP passes, along with a slight decrease in elongation. The fracture morphology also changes from many deep dimples before ECAP to many small dimples after ECAP application, denoting a typical ductile fracture of the pearlitic steel