Investigation of the origin of compressive residual stress in CVD TiB2 hard coatings using synchrotron X-ray nanodiffraction

Complementary High Spatial Resolution Methods in Materials Science and Engineering

“…Error bars report the standard deviation of an average of 20 points measured per loading/ stress step. [79] The presented results for the TiN/TiB 2 coating clearly demonstrate the powerful synchrotron X-ray nanodiffraction technique for determination of the microstructural evolution as a function of the thickness of nanocrystalline coatings. grained TiN base-layer, both deposited within one deposition run using chemical vapor deposition (CVD), are shown.…”

“…[78] It combines the benefits of 2D XRD in transmission geometry and highly focused synchrotron nanobeams with beam diameters below 50 nm, allowing the determination of the whole microstructural fingerprint of nanocrystalline coatings as a function of their thickness with a spatial resolution below 50 nm. [79] Next to the substrate/coating interface, the TiN base-layer exhibits a rather small grain size, which increases with increasing coating thickness, typical for competitive growth. The lamella is, then, mounted on a piezo translation stage and its interface aligned with respect to the X-ray nanobeam to minimize sample tilt.…”

“…Thus, for each individual measurement (i.e., each step) the Debye-Scherrer rings can be evaluated providing information on phase composition, domain size, texture, and residual strain/stress. [79] The residual stress profile in Figure 12c was determined from the elliptical distortion of the Debye-Scherrer rings obtained from synchrotron X-ray nanodiffraction at the ID13 beamline, European Synchrotron Radiation Facility (ESRF) in Grenoble, France according to ref. 11.…”

Progress in development of coated indexable cemented carbide inserts for machining of iron based work piece materials

“…The CVD TiCN coatings consists of a TiN interlayer (0.7 µm), a medium temperature TiCN layer (5.8 µm) [14], a bonding layer and corundum type α-Al 2 O 3 layer in 0001 texture (3.5 µm). The CVD TiB 2 coating is deposited on a 1 µm TiN interlayer and shows despite most CVD coatings residual compressive stresses [10]. The microstructure of the coatings is shown in Figure 2.…”

“…For some special applications like milling of stainless austenitic steels and titanium alloys an outstanding coating system is CVD TiB 2 which is covered within this work. [10,11] The further development of steels in high demanding applications like gas turbines regarding high temperature strength and creep resistivity, lead to difficult du machine materials with high demands on the cutting tool. Beside the machining strategy, macro and micro geometry of the tool as well as machining conditions, the proper choice of insert grade is crucial.…”