Papers by Author: Kantesh Balani

Abstract: In the present work, Mg - 9wt. % Li - 7% wt. Al – 1 wt. % Sn (LAT971) alloy was cast and hot rolled at ~573K. Phase analysis of LAT971 revealed the presence of dual phase structure namely Mg-rich α- and Li-rich β-phase. After hot rolling, it was observed that dynamic recrystallization led to refinement of the α-phase grain structure. Significant crystallographic texture evolution, characterized by electron backscatterd diffraction, revealed increased activity of the non-basal (101 ̅0) slip plane after conventional hot rolling process.

Abstract: Mg-Li based alloy, namely Mg-9%Li-5%Al-3%Sn-1%Zn (LATZ9531) was cast and consequently hot rolled at ~573K. In the present study, as cast and hot rolled structural features has been investigated by scanning electron microscope and electron back scattered diffraction (EBSD). Phase analysis revealed presence of major Mg-rich α-phase and Li-rich β-phase. Significant crystallographic texture evolution due to conventional hot rolling process was observed due to the increased activity of the non-basal slip mode.

Abstract: Emergence of engineering nanomaterials to render exceptional properties require understanding the thermodynamics and kinetics of grain growth and eliciting role of grain boundary mobility therein. Grain boundary mobility in alumina (Al2O3) has shown several repercussions on the evolution of microstructure to render drastic differences in the mechanical- (hardness, yield strength), optical- (transmittance), electrical- (conductivity), magnetic- (susceptibility), and electrochemical- (corrosion) properties. Consequently, the role of surface energy and the effect of temperature in equilibrating the grain shape and size are presented herewith. Several statistical or deterministic computational modeling have been attempted by researchers to elicit the dominating grain growth mechanisms. But, the limitations extend from the memory of computer and number of atoms in a simulation, or feeding the boundary conditions without incorporation of the initial microstructure to arrive at the dominating growth mechanism parameters. Contrastingly, the role of dopants in Al2O3 to either enhance or impede the grain growth is presented via various complexions responsible for transitions at the grain boundary interface. Six complexions resulting various grain boundary interface, strongly affect the grain boundary mobility, and sideline the dopant contributions in deciding the overall grain boundary mobility. It has also been presented that grain growth exponent increases with decreasing grain size, and additionally, secondary reinforcement of carbon nanotube (CNT) in Al2O3 impedes the grain mobility by as much as four times. The effect of temperature is found to be more pronounced, and has shown to enhance the grain boundary mobility by as much as six orders of magnitude.