Papers by Keyword: Cu Precipitation

Abstract: The precipitation of copper during aging at 600oC in high-purity Fe-Cu alloy was examined by means of transmission electron microscopy (TEM).Nano-scale copper-rich clusters with a B2-like structure were observed during heat treatment. These micro structural features play an important role in precipitation strengthening. In addition, the precipitation process has been analyzed in terms of the evolution of microstructure by a Monte Carlo method. A description of the coherent precipitation of copper in iron, based on a vacancy diffusion mechanism, thermally activated jump frequencies and cohesive energy is discussed in order to deal with simultaneous precipitation of metastable and stable phases in Cu-containing steel during aging. This analysis gives an estimation of the precipitation dynamics, as well as the evolution of Cu precipitates across a wide range of temperatures.

Abstract: Effect of the third alloying element Mn on Cu-precipitation was studied in a binary Fe-1.3% Cu alloy. Precipitation in both the alloys was investigated after homogenization treatment and subsequent artificial aging. Advanced characterization techniques such as Positron Annihilation Spectroscopy (PAS) and Tomographic Atom Probe (TAP) were used to establish the chemical composition, morphology, size and number density of the Cu-rich phases. Combined results of PAS and TAP were particularly useful in order to follow the Cu precipitation in the binary alloy. At short aging times, addition of Mn significantly increased the kinetics of hardening while its effect on the magnitude of precipitation strengthening is only marginal. It further increases the over-aging kinetics.