A D V A N C E D M A T E R I A L S & P R O C E S S E S | J U L Y / A U G U S T 2 0 2 1 5 6 iTSSe TSS iTSSe TSS 10 inform the FE parameters to model the fracture and adhesion of the particle on the substrate. (Fig. 2) SLIDING WEAR OF CONVENTIONAL AND SUSPENSION SPRAYED NANOCOMPOSITE WC-CO COATINGS: AN INVITED REVIEW R. Ahmed, O. Ali, C.C. Berndt, and A. Fardan This paper provides an expert review of the tribological considerations that dictate the sliding wear performance of thermal spray WC-Co coatings. Structure–property relationships and failure modes are discussed to grasp the design aspects of WC-Co coatings for tribological applications. Recent developments of suspension sprayed nanocomposite coatings are compared with conventional coatings in terms of performance and failure mechanisms. The dependency of coating microstructure, binder material, carbide size, fracture toughness, post-treatment, and hardness on sliding wear performance and test methodology is discussed. Semiempirical mathematical models of wear rate related to the influence of tribological test conditions and coating characteristics are analyzed for sliding contacts. Finally, advances for numerical modeling of sliding wear rate are discussed. (Fig. 3) the nonlinear and time-dependent response of polymer deformation during the cold spray impact with both rigid and deformable particles. The particle’s material properties, particle velocity, and particle size were systematically studied to obtain the polymer deformation’s various responses from finite element analysis. Particle impact velocity was experimentally measured with a double disk rotary system. (Fig. 4) ESTABLISHING A COLD SPRAY PARTICLE DEPOSITION WINDOW ON POLYMER SUBSTRATE Jung-Ting Tsai, Semih Akin, Fengfeng Zhou, David F. Bahr, and Martin Byung-Guk Jun A set of processing conditions for cold spray deposition of an embedded particle layer on a polymer substrate has been established using a dynamic impact model and verified experimentally. This research utilizes a three-network polymer model based on high strain-rate impact tests to capture 11 Fig. 3 — Shear stress distribution under pure rolling and pure sliding conditions (R. Ahmed, Rolling Contact Fatigue, ASM Handbook, Vol 11: Failure Analysis and Prevention, 2002). Fig. 4 — Mesh geometry and the schematic view of the FE model. PS-PVD ALUMINA OVERLAYER ON THERMAL BARRIER COATINGS AGAINST CMAS ATTACK Yiqian Guo, Liangliang Wei, Qing He, Yangpi Deng, Wenting He, and Hongbo Guo Glassy deposits mainly comprising of calcium–magnesium–alumina–silicate (CMAS) accelerate the spallation of thermal barrier coatings (TBCs). In thiswork, anAl2O3 layerwas produced on yttria-stabilized zirconia (YSZ) coating by plasma spray–physical vapor deposition (PS–PVD). The effects of processing parameters during PS–PVD process on the microstructures of the deposited Al2O3 coatings were investigated. A homogeneous Al2O3 coating with porosity less than 1% was deposited at the spray distance of 1400 mm, which is much denser than the coating produced by atmospheric plasma spray (APS) and other PS–PVD coatings sprayed at 1000 and 1900 mm. (Fig. 5) Fig. 5 — Surface morphologies of feedstock powder for spraying Al2O3 coatings: (a) lower magnification and (b) higher magnification. JTST HIGHLIGHTS
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