1 Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark2 Department of Mechanical Engineering, Technical University of Denmark3 Centre for oil and gas – DTU, Center, Technical University of Denmark
Low-temperature gaseous carburizing of stainless steel is associated with a colossal supersaturation of the fcc lattice with carbon, without the development of carbides. This article addresses the simultaneous determination of stress and composition profiles in layers of carbon xpanded austenite obtained by low-temperature gaseous carburizing of AISI 316. X-ray diffraction was applied for the determination of lattice spacing depth profiles by destructive depth profiling and reconstruction of the original lattice spacing profiles from the measured, diffracted intensity weighted, values. The compressive stress depth distributions correlate with the depth distribution of the strain-free lattice parameter, the latter being a measure for the depth distribution of carbon in expanded austenite. Elastically accommodated compressive stress values as high as -2.7 GPa were obtained, which exceeds the uniaxial tensile yield strength by an order of magnitude.
Metallurgical and Materials Transactions a - Physical Metallurgy and Materials Science, 2009, Vol 40A, Issue 8, p. 1791-1798