Influence of grain refiner addition and heat treatment on the mechanical properties of Al-Si alloy
In the present investigation, an attempt is made to study the effect of addition of grain refinement on Al-Si alloy, when it is subjected to the combined grain refiner addition (Al-5T-1B) and subjected to mechanical vibration and heat treatment. The material is tested for hardness property and dry sliding wear properties. The results of the present investigation indicate that there is a considerable improvement in the hardness valves, microstructure and resistance for wear.
Effect of grain refinement and modification on the dry sliding wear behaviour of eutectic Al–Si alloys
Abstract The present study deals with an investigation of dry sliding wear behaviour of grain refined and or modified eutectic (Al–12Si) Al–Si alloy by using a Pin-On-Disc machine. The indigenously developed Al–1Ti–3B and Al–10Sr master alloys were used as grain refiner and modifier for the grain refinement of α -Al dendrites and modification of eutectic Si, respectively. Various parameters have been studied such as alloy composition, sliding speed, sliding distance and normal pressure. The cast alloys, master alloys and worn surfaces were characterized by SEM/EDX microanalysis. Results suggest that, the wear resistance of eutectic Al–Si alloys increases with the addition of grain refiner (Al–1Ti–3B) and or modifier (Al–10Sr). Further, the worn surface studies show that adhesive wear was observed in Al–12Si alloy in the absence of grain refiner and modifier. However, an abrasive and oxidative wear was observed when the grain refiner and modifier are added to the same alloy. Commercially available LM-6 (12.5%Si) alloy was used for comparison.
Friction and wear behaviour of cast hypereutectic Al-Si alloy (LM28) atlow sliding velocities
In the present paper, effect of contact pressure and low sliding speed on dry sliding oxidative wear resistance of experimental alloy LM 29 (Al-17Si-1.2Cu-0.8Ni-0.6Mg) has been investigated. Experimental alloy produced byfoundry technique was modified - refined by using red phosphorus and Al-5Ti-1B master alloy. Refined-modified alloy was given T6 age hardening heat treatment. PIN-ON-DISC type friction and wear testing machine (DUCOM, INDIA) was used for wear behaviour study of as-cast, modified-refined, and heat-treated alloy. Dry sliding wear test was performed at different contact pressures (0.35, 0.7 & 1.05 MPa) and sliding speeds (0.2, 0.5. & 0.9 m/s). It was found that contact pressure has non-linear relationship with wear rate and which also is affected by sliding speed. At low sliding speed i.e. 0.2 m/s, wear rate increases linearly with the contact pressure. No major increase in wear rate was noted with increase of contact pressure at comparatively high sliding speed say 0.5 or 0.9 m/s. Friction force was found to decrease with increase in sliding speed. Bulk temperature rise due to frictional heating was found higher for as-cast alloy than the refined-modified or age hardened alloy under simiiar sliding conditions.