Abstract No.:	3842
Scheduled at:	Thursday, May 22, 2014, Hall H3 2:00 PM Cold Gas Spraying 3
Title:	Deposition mechanisms of cold sprayed Zr-based metallic glass
Authors:	Giovanni Bolelli / Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Italy Andrea Lenzotti / Dipartmento di Ingegneria , Italy Alex List/ Helmut Schmidt University, Germany Frank Gärtner/ Helmut Schmidt University, Germany Jochen Heinrich/ Universität des Saarlandes, Germany Ralf Busch/ Universität des Saarlandes, Germany Luca Lusvarghi*/ Dipartmento di Ingegneria , Italy Thomas Klassen/ Helmut Schmidt University, Germany
Abstract:	Compared to other thermal spray processes, the cold spraying technique, due to the lower gas temperature, allows the use of entirely new categories of materials as feedstock powders. Specifically, this study investigated the cold spray deposition of an amorphous AMZ4 alloy with composition Zr59.3Cu28.8Al10.4Nb1.5, which is a modification of the more conventional Vitreloy composition aiming to reduce materials costs. The study particularly focuses on particle impact behavior and aims to identify proper conditions for optimal bonding between particles and substrate. For studying impact morphologies under different process conditions (process gas temperatures and pressures), wipe tests were performed onto steel substrates. Distinct types of impact morphologies were observed by SEM. Categories range from indents/rebounds over embedded undeformed particles and plastic deformation to viscous flow behaviour. The frequency of each impact type was related to the different process parameters, and respective adhesion strength for certain impact morphologies was investigated by cavitation testing. The results show that higher process gas pressures or temperatures lead to more viscous deformation and yield better adhesion properties. This investigation gives new insights into the deposition mechanisms of amorphous materials in cold spraying, and is the basis for determining optimum process parameter windows for coating formation. Respective coatings produced under optimized parameters will also be presented.

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