R Ramanujam

Bio: R Ramanujam is an academic researcher from VIT University. The author has co-authored 1 publications.

Mathematical modeling and optimization of tribological behaviour of Al 7075 based hybrid nanocomposites

Abstract: Many industrial applications necessitate lightweight materials that possess better tribological behaviour. Whilst aluminium based nanocomposites are proposed owing to their lightness, their tribolo...

Tribological Properties of Al 7075 Composite Reinforced with ZrB2 Using Grey Relational Analysis

Abstract: In this work, the authors investigate the optimal tribological parameters of Al 7075 composite reinforced with ZrB2 using Grey Relational Analysis (GRA). Initially, the composite specimens were prepared by the variation of reinforcement 5%, 10% and 15% using stir casting routing method. Further, the developed metal matrix composites are used to measure the wear and frictional properties on pin-on – disc testing apparatus. The input parameters such as, wt% of reinforcement (5%, 10% and 15%), load (4.92N, 9.81N and 14.72N) and the time required for conducting the wear test is (15 min. 30 min and 45 min). A Taguchi L9 orthogonal array was designed for conducting the number of experiments. Based on the combination of number of experiments wear study has been conducted on the wear testing apparatus. Moreover, GRA was used for obtaining the best optimal input control parameters that gives minimum magnitude of wear and coeffi cient of friction (COF). Finally, the confi rmatory experiments are conducted and verifi ed with the Taguchi grey relational analysis. The results shows that the predicated optimal mean value is almost similar to the experimental value.

Identification of self-lubricative mode for the ultrasonic treated AA6061-B4C-CNT hybrid composites

Abstract: This research investigates the self-lubricative behavior of boron carbide (B4C) and carbon nanotube (CNT) reinforced 6061 aluminium alloy hybrid composites. Hybrid composites were prepared by varying the volume percentages (5–15%) of B4C and CNT. Novel ultrasonic vibration (frequency of 20 kHz and power of 2.5 kW) assisted stir casting process was used for fabricating hybrid composites. A pin-on-disc type tribometer mounted with EN-8 as the counterface material was used to evaluate the friction and wear behavior of hybrid composites under dry sliding conditions. Normal loads ranging from 15–45 N and sliding speeds ranging from 1–2 m/s were applied during the experiments. The self-lubricative properties of different hybrid composites were assessed through the examination of the worn surface of pins using surface characterization techniques such as Scanning electron microscopy, Electron dispersive spectroscopy and Raman spectroscopy. The experimental results indicated that the addition of CNT particles increased the hardness of hybrid composites. The matrix strengthening efficiency of CNT was found to be greater at 10 vol.% of B4C, indicating a maximum hardness ranging from 102 to 109 VHN. In comparison, 10 vol.% of CNT hybrid composites showed superior tribological performance at all wear testing conditions. The mode of wear of hybrid composites suggested by the analysis on the worn pin surface was as follows: Scarce (5 vol.% CNT), Tribolayer (10 vol.% CNT) and Fracture (15 vol.% CNT).