Ti particle-reinforced surface layers in Al: Effect of particle size on microstructure, hardness and wear

• Published in: Materials characterization 2010-11, Vol.61 (11), p.1126-1134
• Main Authors: Mordyuk, B.N., Silberschmidt, V.V., Prokopenko, G.I., Nesterenko, Yu.V., Iefimov, M.O.
• Format: Article
• Language: English
• Subjects: Abrasive wear; ALUMINIUM; Aluminum; ANNEALING; Applied sciences; COMPOSITE MATERIALS; Cross-disciplinary physics: materials science; rheology; Dispersion hardening metals; Exact sciences and technology; GRAIN SIZE; Intermetallic compounds; Intermetallics; LAYERS; MATERIALS SCIENCE; MATRIX MATERIALS; Metals. Metallurgy; MICROHARDNESS; Microstructure; PARTICLE SIZE; Particle-reinforced composite; PARTICLES; Particulate composites; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; PLASTICITY; Powder metallurgy. Composite materials; Production techniques; REINFORCED MATERIALS; Reinforcement; SCANNING ELECTRON MICROSCOPY; SHOT PEENING; Solidification; SURFACES; Titanium; TRANSMISSION ELECTRON MICROSCOPY; Ultrasonic impact peening; WEAR; WEAR RESISTANCE; X-RAY DIFFRACTION
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2010.07.007

Two types of Ti particles are used in an ultrasonic impact peening (UIP) process to modify sub-surface layers of cp aluminium atomized, with an average size of approx. 20 μm and milled (0.3–0.5 μm). They are introduced into a zone of severe plastic deformation induced by UIP. The effect of Ti particles of different sizes on microstructure, phase composition, microhardness and wear resistance of sub-surface composite layers in aluminium is studied in this paper. The formed layers of a composite reinforced with smaller particles have a highly misoriented fine-grain microstructure of its matrix with a mean grain size of 200–400 nm, while reinforcement with larger particles results in relatively large Al grains (1–2 μm). XRD, SEM, EDX and TEM studies confirm significantly higher particle/matrix bonding in the former case due to formation of a Ti 3Al interlayer around Ti particles with rough surface caused by milling. Different microstructures determine hardness and wear resistance of reinforced aluminium layers: while higher magnitudes of microhardness are observed for both composites (when compared with those of annealed and UIP-treated aluminium), the wear resistance is improved only in the case of reinforcement with small particles.