|About this Abstract
||Materials Science & Technology 2012
||Steel Product Metallurgy and Applications
||The Effect of Silicon on the ε --> θ Transformation in Ultra-Strong Spring Steels
||Bij-Na Kim, David San Martín, Jesús Chao, Pedro E.J. Rivera-Díaz-del-Castillo
|On-Site Speaker (Planned)
Tempered martensitic steels have shown considerable strengthening by controlled nanoprecipitation of the transitional ε-carbide, a precursor to cementite. Initial studies have been carried out in a spring steel model alloy of composition Fe-0.55C-2.2Si wt.%. Carbon was chosen as a carbide former, and silicon because of its inhibiting effect in the cementite transformation from epsilon. Tempering was carried out in order to understand the transformation mechanism. The classical nucleation theory was used in order to understand the carbide transition. Both formation and misfit strain energies have been modelled in order to explain precipitation behaviour. Mechanical tests have shown that in the transformation regime there was a loss in strength and an increase in ductility. Albeit the apparent simple alloy composition, yield strengths above 2.4 GPa were obtained. Analysis of the microstructure was carried out in a systematic manner in order to statistically distinguish precipitation behaviour during tempering.
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