Electron microscopy study of reaction layers between single-crystal WC particle and Ti–6Al–4V after laser melt injection

✍ Scribed by Liqun Li; Dejian Liu; Yanbin Chen; Chunming Wang; Fuquan Li

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 811 KB
• Volume: 57
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2009.04.021

✦ Synopsis

Laser melt injection of single-crystal WC particles (WC p ) into Ti-6Al-4V was demonstrated to produce functionally graded materials (FGMs). A detailed electron microscopy examination was performed to study the microstructure of the FGMs. A thermal simulation experiment was designed to clarify the existing controversy about the formation of the W 2 C reaction layer. Twinning deformation occurred in the W 2 C layer can explain the absence of orientation relationships between the W 2 C layer and the parent phase WC during solid-phase transformation. A new W layer with a thickness of 200-300 nm at the WC p /Ti reaction zones is found. As a diffusion barrier, this W layer can suppress further dissolution of WC p and inhibit interfacial reactions. Although particle cracking is still the main failure mechanism, the tensile strength of the composites is increased by at least 17% when granular WC p is used instead of single-crystal WC p .