Migration of Carbon in Tempered Martensitic Steel During Excimer Laser Melting

Abstract

ABSTRACTThe migration of ion implanted 13C in tempered martensitic steel (nominal composition 1.05 wt. % C, 0.2 wt. % Si, and 0.3 wt. % Mn) during excimer laser melting was examined utilizing the resonance of the l3C(p,γ)14N reaction at Ep = 1747.6 keV. Depth concentration profiles after five and ten laser pulses of 1 J/cm2 revealed a deviation from random walk diffusion in a homogeneous media. This was modelled by using partitionless solidification and solubility controlled flow of carbon in the iron-carbon melt. A diffusion length of nm during the period to τ the melted phase was deduced. Ion implanted surfaces were initially crystalline but significant crystalline to amorphous transformation occurred following laser treatment.