AbstractResidual stresses in chemically vapour deposited (CVD) TiC and TiN coatings on various substrates were measured using X-ray diffraction. A quantitative prediction of the vaiue of the strain (and stress) was obtained from the difference in thermal shrinkage between layer and substrate on cooling from the CVD temperature to room temperature. The sign of the strains measured always agreed with the prediction, but in a number of cases the absolute value of the elastic strain measured was smaller than that predicted. For layers on iron and Fe-1.0 wt-%C substrates this difference is caused by strain accommodating processes in the substrate, mainly during phase transformations. For TiN layers on molybdenum and tungsten substrates, strain accommodating processes occur in the layer, and these may originate in the microstructure of the layer.