Internal residual stress of sintered Fe-Cr/TiN composite measured with neutron diffraction

Sintered chromium alloy containing titanium nitride has high wear- and heat resistance. This material has been developed for the valve seat insert, which is a part of diesel engines in automobiles. In this study, the neutron diffraction technique was used to carry out internal stress measurements of composite material manufactured by powder metallurgy. The purpose of this study is evaluating the internal phase stresses of metal matrix composites. Changes of phase stresses under the tensile loading were measured. Influence of the inclusion (titanium nitride) on residual stress in each phase (so-called phase stress) was examined. Neutron diffraction data obtained from both phases were compared to the Micromechanics model based on Eshelbys approach and the Mori-Tanaka theorem. It was found that phase stress agrees well with the theoretical estimation. (author)