Mechanical and surface analysis of Ti0.4Al0.6N/Mo multilayers

Abstract

The quest for hard materials that are able to sustain elevated stresses as tools or cutting processes has led to the investigation of (Ti,Al)N/Mo multilayer coatings. These structures have been deposited by dc magnetron sputtering on high-speed steel and stainless-steel substrates and designed with modulation periods of approximately 13 nm, up to a total thickness of 2.8 m. Experimental X-ray di!raction (XRD) achieved the basics involving structural quality and texture while RBS provided the composition. From AFM observations the waviness of the surface was monitored and it was found that the rms roughness values were minimised for a bias voltage of !120 V. Ultramicrohardness values of 33 GPa were obtained for the best samples, and their adhesion to the steel substrates was also studied. Residual stress measurements revealed a compressive stress state that prevailed in these structures, ranging from !0.2 to !1.3 GPa.

Optimization and thermal stability of TiAlN/Mo multilayers

“…XRD h-2h scans, both in symmetric and asymmetric modes, were performed using Brucker AXS D5005 and Philips X-Pert diffractometers with Cu-Ka radiation. The low-angle XRD refinement program Suprex [9,10], using the optical theory developed by Underwood and Barbee [11], was used as a fitting procedure that enabled a precise determination of the relative thickness of each material in a bilayer, interdiffusion width (t id ) at the interface and the overall interfacial roughness (r rms ), being its calculation procedure described elsewhere by the authors [7].…”