Pearlite

About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.

Micromechanical modeling of ferritic/pearlitic steels

Abstract: A two-dimensional micromechanical model based on the Voronoi algorithm is presented to model two-phase ferritic/pearlitic steels. Special care is taken to generate periodic grain structures as well as periodic finite element meshes. The model is evaluated by generalized plane strain finite element calculations, periodic representative cells are generated with the desired volume fraction pearlite. Loading by an arbitrary combination of average stresses or strains is possible by application of periodic boundary conditions. Uniaxial tension tests are performed on pure ferrite and pearlite specimens, as well as on materials containing 25 and 58% pearlite. Modeling of the two-phase materials was performed by using the stress-strain curves of the pure phases, in the description of the plastic properties. Comparisons between generated data and experiments at a loading strain of 2% show good agreement. Moreover, local stresses and strains are studied within the different unit cells. In addition, the model is used to investigate the plastic behavior under biaxial loading. It is shown that Hill's yield criterion gives a good fit to the numerical data.

Austempered Ductile Iron (ADI): Influence of Austempering Temperature on Microstructure, Mechanical and Wear Properties and Energy Consumption

Abstract: Alloyed Ductile iron, austenitized at 840 °C for 30 min in a special sealed austempering furnace, was austempered for 30 min in molten salt mixture at 4 trial temperatures of 300 °C, 320 °C, 340 °C and 360 °C. Tensile strength, yield strength, percentage elongation and impact energy were evaluated for the as-cast and austempered samples. Microstructures were investigated using microscopy, coupled with analyzing software and a scanning electron microscopy. The specific wear of samples was tested using pin-on-disc wear testing machine. X-ray diffraction was performed to calculate the amount of retained austenite present in the ausferrite matrix. As-cast microstructure consists of ferrite and pearlite, whereas austempered ductile iron (ADI) contains a mixture of acicular ferrite and carbon enriched austenite, called “ausferrite”. Hardness and strength decreased, whereas ductility and impact strength improved with an increase in the austempering temperature. XRD analysis revealed that the increase in austempering temperature increased the retained austenite content. A decrease in wear resistance with austempering temperature was observed. Modified Quality Index (MQI) values were envisaged, incorporating tensile strength, elongation and wear resistance. MQI for samples austempered at 340 °C and 360 °C showed a better combination of properties. About an 8% reduction in energy consumption was gained when the heat treatment parameters were optimized.

Investigations on Microstructures and Three-Body Abrasive Wear Behaviors of Fe–B Cast Alloy Containing Cerium

Abstract: The effect of the element cerium on the microstructure and wear behavior of Fe–B cast alloy was investigated by scanning electron microscope, transmission electron microscope, X-ray diffraction analysis, Leica digital image analysis, hardness tester and abrasion tester. The microstructures of as-cast Fe–B alloy are composed of the phase ferrite, pearlite and eutectic boride. Moreover, the as-cast eutectic boride structures in Fe–B alloy containing cerium are finer than that in the alloy having no cerium. After heat treatment, the average boride area and wear weight loss of the alloy containing cerium are lower than these of the alloy having no cerium. Before the formation of primary austenite, cerium can combine with oxygen to form Ce2O3. Ce2O3 can act as nuclei of primary austenite, promoting the refinement of austenite and borides during solidification, and improve the wear property of Fe–B alloy.