|
5319 |
|
Wednesday, June 07, 2017, Hall 14 2:20 PM Medical Industry II |
|
Microstructure and mechanical properties of cold sprayed titanium coatings |
|
Wojciech Zórawski / Kielce University of Technology, Poland Janusz Mdry/ PZL Mielec, Poland JarosBaw Sienicki*/ PZL Mielec, Poland Medard Makrenek/ Kielce University of Technology, Poland Anna Góral/ Institute of Metallurgy and Materials Science PAS, Poland Szymon Kowalski/ Tegeno Ltd., Poland |
|
The work concerns a study of the properties of cold sprayed Ti coatings. This material is an attrac-tive choice for many applications because it exhibits high strength-to-weight ratios, very good oxi-dation resistance, corrosion resistance and biocompatibility. Cold spraying is applied to deposit Ti coatings and elements as additive manufacturing process, however it needs higher critical velocity for deposition than other, more ductile metals. Nowadays nitrogen as cheap gas is used as working gas in cold spray process, however application helium as accelerating gas allows to obtain elements with higher strength. It allows to understand the mechanism of cohesion between sprayed particles. In carried out experiment Ti powder with angular shape was applied in the cold spraying process. The coatings were sprayed by means of Impact Innovations 5/8 system with nitrogen and helium onto 7075 Al alloy. The microstructure and composition of powders and coatings were analyzed by SEM FEI Novaä NanoSEM 200 and TEM (FEI TECNAI G2). Their phase composition and resid-ual stress were studied with the use of a Bruker D8 Discover diffractometer. Residual stresses in the coatings were determined using sin2y method. Microhardness was measured with a Vickers indenter. The topography of the coatings were analyzed by means of a Talysurf CCI-Lite non-contact 3D profiler. Mechanical properties were performed with Nanovea tester. The investigations revealed that the cold sprayed Ti coatings with helium as working gas exhibit better mechanical properties, lower roughness and lover level of residual stresses. |