Nanoscale co-precipitation in a novel high-strength low-carbon steel is studied in detail after isothermal aging. Atom-probe tomography is utilized to quantify the co-precipitation of co-located Cu precipitates and M2C (M is any combination of Cr, Mo, Fe, or Ti) carbide strengthening precipitates. Coarsening of Cu precipitates is offset by the nucleation and growth of M2C carbide precipitate, r...

In this work, the evolution of MC-type Nb-rich primary carbides in a 35Ni-25Cr-Nb-type refractory alloy, commonly known as HP40-Nb, and its transformation into Ni-Nb silicide G-phase (Ni16Nb6Si7), has been studied. For purpose, experimental technique scanning electron microscopy was used together with X-ray microanalysis to detect changes chemical composition niobium carbide over time at given ...

High temperature microscopy during oxidation of austenitic stainless steels shows that an increased rate of oxidation is found in a narrow zone along grain boundaries where chromium carbides have been precipitated. This lends support to the chromium-depletion theory of intercrystatline corrosion of these steels. Approximate solution of the appropriate diffusion problem shows good agreement with...

In this study, the changes in microstructure of HP-Nb cast heat resistant steel after 8 years of service at high temperatures were investigated. Study of microstructure using optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive spectrometry (EDS) showed that the microstructure of this steel in as-cast condition includes an austenitic matrix, and that...

A new pyrolysis technology involving chromium is proposed for the determination of δD in alkanes based on systematic analysis reaction temperature, conversion rate, and mechanism. Compared with traditional high-temperature (HTC) method, our findings suggest that chromium/high-temperature (Cr/HTC) can improve rate hydrocarbons reduce required temperature by up to 175 °C; meanwhile, increased an ...