Microstructure and Mechanical Properties of Granular Pearlite Steel After Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) of granular pearlite high carbon steel was carried out at room temperature via the Bc route. The microstructure evolution was investigated by means of scanning and transmission electron microscopy, and the mechanical properties of granular pearlite steel were measured by tensile and microhardness testing. After four passes, the microstructure was obviously refined. An ultrafine microduplex structure with 400 nm equiaxed ferrite grains and 200 nm cementite particles were formed. The yield strength, ultimate tensile strength, microhardness, and the ratio of the yield to tensile strength increased with the number of ECAP passes, however, the elongation slightly reduced. The tensile fracture morphology changes gradually from ductile fracture to ductile and quasi-cleavage mixed fracture.