Papers by Keyword: OFHC Copper

Abstract: Grain boundary character distributions (GBCD) of OFHC copper equal-channel angular pressing (ECAP) deformed and then annealed were analyzed by electron back scatter diffraction (EBSD). The experimental results showed that a combination of ECAP deformation and annealing treatments could significantly increase the fraction of low-Σ coincidence site lattice (CSL) boundaries (Σ≤29) and effectively interrupt the connectivity of random boundaries network in OFHC copper. An increase of low-Σ CSL boundaries from 45.27 to 71.06% was observed in as-received material after one pass ECAP strain followed by annealing at 350 °C for 48 h. The connectivity of random boundaries network was interrupted by high fraction of low-Σ CSL boundaries.

Abstract: Micro dimples have been generally considered as a valuable texture which can improve lubrication and reduce wear of the sliding surfaces by acting as reservoirs of lubricants and grinding debris. Laser shock processing (LSP) is an innovative surface treatment technology which can modify metals and shape metallic parts accurately. In this study, a new process for micro dimple fabrication which could be called laser peen texturing (LPT) was proposed based on LSP. LPT experiments were performed on Oxygen-Free High Conductivity (OFHC) copper. Influences of experimental parameters on geometrical characteristics of micro dimples were investigated. It was found that after LPT, the pile up was generated around the dimple .The diameter, depth and aspect ratio of the micro dimples increase with the laser power density and repeated shock number, but all of them saturated gradually. From matellographic analysis, grain refinement was observed obviously beneath the dimple.

Abstract: Miniature parts with high accuracy and precision are increasingly in demand for various industries. Microturning is a process for fabrication of such miniaturized parts with features that range from tens of micrometres to a few millimetres. In this present study commercially available Oxygen Free High Conductivity (OFHC) copper rods have been microturned using cermet inserts of 0.1mm nose radius. The effects of machining parameters on the surface generated have been discussed. Scanning electron microscope images of worn out inserts and machined surfaces are analysed to ascertain the wear mechanism and study the nature of the surface generated.

Abstract: This work presents the results of a study on textural and microstructural inhomogeneities that develop during annealing of heavily drawn Oxygen free high conducting (OFHC) copper wire. The wire was drawn at room temperature to a true strain of 2.31 and isothermally annealed at 750°C for annealing times ranging from 10s to 1hr. The inhomogeneity of microstructure across the wire was clearly visible as three distinct concentric regions, which were classified as: the inner core, the mid section, and the outer surface. Two texture transitions were observed. At shorter annealing time, recrystallization which originated from the mid section, resulted into a strong<100>+weak<111> duplex fiber texture. However, prolonged annealing gave rise to abnormal grain-growth that proceed from the mid section to the outer surfaces with a dominant <111> fiber component at the mid and inner region, and mixed components of <111>, <100>, and <112> at the outer surfaces.

Abstract: Deformation and recrystallization texture has been investigated in Oxygen free high conducting (OFHC) copper wires drawn at room temperature to true strain of 2.31, and isothermally annealed at various temperatures between 150°C and 750°C. Local orientations of the microstructures were measured by means of electron backscattered diffraction (EBSD) technique. While the drawn wire was characterized by a major<111> + minor<100> duplex fiber texture, recrystallization occurred at annealing temperatures between 250°C and 400°C and resulted into a major<100>+minor<111> recrystallization texture. At temperatures above 500°C, the <100> dominated recrystallization texture changed to the <111> dominated growth texture due to secondary recrystallization, which favored the <111> orientation at the expense of the <100> component.