Experimental evaluation of interfacial adhesion strength of cold sprayed Ti-6Al-4V thick coatings using an adhesive-free test method

SURFACE & COATINGS TECHNOLOGY

卷:381

Article

Boruah, Dibakor^1,2  Robinson, Ben³  London, Tyler³  Wu, Huan³  de Villiers-Lovelock, Heidi⁴  McNutt, Philip³  Dore, Matthew³  Zhang, Xiang¹ 

[1] Coventry Univ, Fac Engn Environm & Comp, Coventry CV1 5FB, W Midlands, England

[2] TWI Ltd, NSIRC, Cambridge CB21 6AL, England

[3] TWI Ltd, Cambridge CB21 6AL, England

[4] Oerlikon Metco WOKA GtnbH, D-36456 Barchfeld Immelborn, Germany

关键词: Adhesion strength;    Cold spray;    Coatings;    Repairs;    Thermal spray;    Ti-6A1-4V;   

DOI  :  10.1016/j.surfcoat.2019.125130

来源: Elsevier

【 摘 要 】

Cold spray (CS) is a rapidly growing solid-state additive material deposition technique often used for repair of high-value metallic components. This study aims at evaluating the interfacial adhesion strength of cold sprayed Ti-6Al-4V (Ti-64) coatings deposited onto Ti-64 substrates for repair applications. An adhesive-free test method, referred as modified Collar-Pin Pull-off Test was developed based on Sharivker's (1967) original design, in order to overcome the limitations of existing test approaches (both adhesive-based and adhesive-free). This method was designed to allow measurement of adhesion strength of high strength coatings such as CS Ti-64, where adhesion strength is higher than 70-90 MPa. A parametric study was performed to assess the effect of coating thickness, scanning speed, track spacing, toolpath pattern, and substrate surface preparation on the coating adhesion strength. A finite element model was also used to evaluate the stress distribution during the pull-off test, and to check the validity of the proposed test method. The proposed adhesive-free test method was found to be capable of measuring coatings with adhesion strengths beyond the upper limit of conventional adhesive-based methods such as ASTM C633. Among the investigated cases, the highest value of coating adhesion strength was measured around 122 MPa, in the case of CS Ti-64 deposited on ground Ti-64 substrates.

【 授权许可】

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