Browsing by Author "Subramani, R Ram"

Now showing 1 - 3 of 3

Impact behaviour of MWCNTs reinforced YSZ and Al2O3 ceramic-nanocomposites prepared via vacuum hot-pressing technique
(Elsevier, 2023-04-24) Subramani, R Ram
Materials for structure-based aerospace applications are on high demand throughout the globe. Owing to its high strength to weight ratio and high stiffness, composites are potential candidates in aerospace, turbine and military applications. This paper concentrates on the impact behaviour of two nanoceramic composites - yttria stabilized zirconia (YSZ) and aluminium oxide (Al2O3) reinforced with multi-walled carbon nanotubes (MWCNTs) prepared via vacuum hot-pressing at 1600 °C with a pressure of 30 MPa at varying MWCNTs contents (1, 3 & 5 wt.%). The composite tiles were examined for impact behaviour using gas gun at different velocities (50, 100 & 200 ms−1). The results indicated that composites with 1 wt% MWCNTs reinforced YSZ demonstrated lower penetration compared to other composites owing to its higher interfacial bonding between MWCNTs and YSZ. On the other hand, alumina reinforced MWCNTs showcased a higher depth of penetration due to weak van der Waals force of attraction between MWCNTs and alumina. The reinforcement of CNTs up to 3 wt.% worked as threshold for improvement in impact behaviour for ceramics whereas penetration values increase with increase of MWCNTs.
Influence of ceramic nanoparticles on fatigue life of Al 6061 prepared via ultrasonic aided rheo- squeeze casting process /
(Taylor & Francis, 2023-04-27) Subramani, R Ram
The fatigue behaviour of Al 6061 along with its ceramic nanoparticles reinforced cermets fabricated through ultrasonic-aided rheo-squeeze casting technique are evaluated. The fatigue behaviour was studied under ambient and elevated temperature (250°C) conditions, and the effect of notches was also examined under same stress conditions. Al 6061 indicated service life of ~1.15 million cycles at low stress value which dropped to 15,470 cycles with increase in stress magnitude. Al cermet (ALST) shwocased enhanced = fatigue life up to ~35% for hybrid cermet with highest service life of 1.71 million cycles due to load transfer mechanism. In elevated temperature condition, life of Al 6061 dropped by 37%, whereas the reinforced cermets remained higher with ALST revealing high service life cycles. Further, notch indicated drop in fatigue life of Al and its cermets with cermets prevailing better than Al. The elevated temperature notch represented the lowest fatigue life owing to stress concentration as well as the coefficient of thermal expansion mismatch.
Influence of ceramic nanoparticles on fatigue life of Al 6061 prepared via ultrasonic aided rheo- squeeze casting process /
(Taylor & Francis, 2023-04-27) Subramani, R Ram
The fatigue behaviour of Al 6061 along with its ceramic nanoparticles reinforced cermets fabricated through ultrasonic-aided rheo-squeeze casting technique are evaluated. The fatigue behaviour was studied under ambient and elevated temperature (250°C) conditions, and the effect of notches was also examined under same stress conditions. Al 6061 indicated service life of ~1.15 million cycles at low stress value which dropped to 15,470 cycles with increase in stress magnitude. Al cermet (ALST) shwocased enhanced = fatigue life up to ~35% for hybrid cermet with highest service life of 1.71 million cycles due to load transfer mechanism. In elevated temperature condition, life of Al 6061 dropped by 37%, whereas the reinforced cermets remained higher with ALST revealing high service life cycles. Further, notch indicated drop in fatigue life of Al and its cermets with cermets prevailing better than Al. The elevated temperature notch represented the lowest fatigue life owing to stress concentration as well as the coefficient of thermal expansion mismatch.