Browsing by Author "Krishanu Biswas"

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An experimental and theoretical investigation on structure-property correlation of Cu2Mn1Al1−xGax full-Heusler alloy
(Elsevier Ltd, 2022) Shashank Shekhar Mishra; Anurag Bajpai; Thakur Prasad Yadav; Ram Manohar Yadav; Anand B. Puthirath; Liangzi Deng; Moein Adnani; Ching-Wu Chu; Robert Vajtai; Pulickel M. Ajayan; Krishanu Biswas; Nilay Krishna Mukhopadhyay
The present study reports the evolution of microstructure and magnetic properties of Cu2MnAl1−xGax Heusler alloys. The L21 phase, which remained stable up to a Ga substitution of x = 0.3, transformed into mixed phases, i.e., hexagonal close packed (HCP) and complex cubic structure (CCS) on further addition of Ga. The non-monotonic increase in the lattice constant indicates that some amount of Ga retains its monovalent state. The magnetic phase showed a transition from ferromagnetic to paramagnetic state with increasing Ga concentration. The re-entrant temperature (TR) decreased from 8.2 K to 5.2 K as Ga content increased from 5 at% to 10 at%. The strength of magnetic exchange-coupling also reduced with an increase in Ga content. Gaussian process regression (GPR) was used to estimate the lattice parameter using the ionic radii and Pauling electronegativity of the constituents. The modeling approach showed high accuracy and stability, providing new insights into future alloy development. © 2021 Elsevier B.V.
Ceramic-based nanocomposites: A perspective from carbonaceous nanofillers
(Elsevier Ltd, 2022) Nidhi Sharma; Tuhina Saxena; Syed Nasimul Alam; Bankim Chandra Ray; Krishanu Biswas; Shikhar Krishn Jha
To overcome the inherent brittle nature of ceramics and to optimize their favorable properties, new design philosophies and novel concepts for manufacturing are needed. Owing to their distinguished mechanical attributes such as strength and stiffness, developing ceramic matrix composites (CMCs) has become the latest penchant for researchers. CMCs are traditionally fibers dispersed in a ceramic matrix (oxide or non-oxide). With the advent of nanoparticles, the probing interests in the field of CMCs are now transforming from traditional reinforcement media (microscale fillers) into new possibilities at the nanoscale. This has brought a new generation of CMCs at nanometric level, commonly known as ceramic matrix nanocomposites (CMNCs). Introduction of nanomaterials like graphene and carbon nanotubes (CNTs) as nano-reinforcements has modified the ceramic-structures at the nanometric level for advanced applications in fields such as automotive, industrial, and aerospace engineering. Lately, a variety of new strategies such as tuning in the presence of dopants, opting pristine dispersion routes and usage of modified sintering techniques have enhanced the distinctive features of the CMNCs. This work summarizes the ongoing advances, recent research, key challenges in the implementation of carbonaceous CMNCs reinforced with graphene and CNTs along with their applications and future prospects. A detailed discussion on the sintering techniques, tribological behavior, strengthening and toughening mechanisms of carbonaceous CMNCs is presented. Various advantages of CMNCs reinforced with graphene and CNTs along with a few drawbacks like the cost and process-limitations have been elaborated. © 2022 Elsevier Ltd
Effect of Ga substitution on structural and magnetic properties of Fe50Mn25Al25-xGax Heusler alloys
(Elsevier Ltd, 2021) S.S. Mishra; T.P. Yadav; Ram Manohar Yadav; Anand B. Puthirath; Liangzi Deng; Moein Adnani; Ching-Wu Chu; Robert Vajtai; P.M. Ajayan; Krishanu Biswas; N.K. Mukhopadhyay; O.N. Srivastava
Heusler alloys possess the structure of an ordered compound while displaying most of the properties of metals. Numerous magnetic exchange mechanisms may be operating in such systems. Herein, the structural and magnetic properties have been investigated as a function of substitution of Al by Ga in Fe50Mn25Al25-xGax (x = 0, 2.5, 5.0, 7.5, 10.0) quaternary (pseudo-ternary) full Heusler alloys. The X-ray diffraction analysis confirms the substituting Al by Ga promoting the lattice expansion in the L21 crystal structure in Fe50Mn25Al25-xGax alloys. The line scanning profile using energy dispersive X-ray analysis investigations suggests the homogeneous distribution of Ga in all the alloys. The magnetic moment of the alloys was found to be affected by Ga as the antiferromagnetic counterpart increases with Ga. A decrease in the value of Curie temperature was found with increase in Ga content. A second-order magnetic phase transition was observed in the alloys above room temperature. © 2020 Elsevier B.V.
Formation and stability of C14 type Laves phase in multi component high-entropy alloys
(Elsevier Ltd, 2020) S.S. Mishra; T.P. Yadav; O.N. Srivastava; N.K. Mukhopadhyay; Krishanu Biswas
The present investigation reports the formation and stability of multi-component AB2-type Laves phase in Ti–Zr–Ni (V, Cr, Fe, Mn, Co)ternary to octonary alloys system. To probe the formation and stability of AB2-type Laves phase in high-entropy alloys, a series of multi-component alloys have been synthesized via melting under protective Ar atmosphere and subsequent annealing at 525 K for 40 h. Systematic investigation has been carried out to understand phase stability using both thermodynamic and parametric approaches. X-ray diffraction measurement and Rietveld analysis indicate the formation of C14 Laves phase in multi-component alloys. The enthalpy of mixing (ΔHmix), size difference (δ) and valence electron concentrations (VEC) have been found to play stellar role in controlling the formation of multi-component Laves phase in these alloys. The valence electron concentrations and electrons per atom ratio (e/a) dictate the choice of elements for the stabilization of Laves phase in these high-entropy alloys. © 2020