University College London - Department of Mechanical Engineering
Abstract
Ti-containing micro-alloyed steels are often alloyed with molybdenum (Mo) to reduce nano-precipitate coarsening, although the mechanism is still disputed. Using small angle neutron scattering we characterised the precipitate composition and coarsening of Ti-alloyed and Ti-Mo-alloyed steels. The results demonstrate ~25 at.% of Ti is substituted by Mo in the (Ti, Mo)C precipitates, increasing both the precipitate volume percent and average size. Mo alloying did not retard precipitation coarsening, but improved lattice misfit between precipitate and matrix, contributing to better aging resistance of the Ti-Mo-alloyed steel. This new understanding opens opportunities for designing aging-resistant micro-alloyed steels with lean alloying elements.
Wang, Yiqiang and Clark, S. J. and Cai, Biao and Venero, Diego and Yun, K. and Gorley, Mike and Surrey, Elizabeth and McCartney, Graham and Seetharaman, Sridhar and Lee, Peter, Small-Angle Neutron Scattering Reveals the Effect of Mo on Interphase Nano-Precipitation in Ti-Mo Micro-Alloyed Steels. Available at SSRN: https://ssrn.com/abstract=3441028 or http://dx.doi.org/10.2139/ssrn.3441028
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