Abstract: Cr, GLC(graphite-like-carbon) and CrTiAlN nanoscaled coatings are deposited by using magnetron sputtering on 45 steel and 40Cr steel of different yield-strength ratios. The influence of the coatings on the ability of elastic deformation of metal matrix is investigated by measuring the changes of elastic modulus and yield stress. The results show that all coatings can improve elastic deformation properties of metal substrate, but the effect on different steel is different. For 45 steel which has lower yield-strength ratio substrate, elastic modulus and yield stress can be enhanced by coatings. When the v =0.1 mm/min, the yield stress of it can be increased 20%. As to 40Cr steel, the coatings can raise elastic modulus markedly but have no effect on yield stress. When the v =0.7 mm/min, the elastic modulus can be increased by 60% on 40Cr sample but only by 22% on 45 steel sample. Different from metal material’s, the elastic modulus of the coating/substrate complex ascends the top then descends gradually with the increase of tensile speed. The prominent hardness and excellent adhesion of coating can inhibit expansion of the deformation area, thereby improving the mechanical properties of the sample.

Key words: Elastic deformation, Elastic modulus, Gradient coating, Magnetron-sputtering ion plating