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S. Sankaran

Bio: S. Sankaran is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Microalloyed steel & Microstructure. The author has an hindex of 19, co-authored 69 publications receiving 898 citations. Previous affiliations of S. Sankaran include University of Münster & University of Louisiana at Lafayette.


Papers
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Journal ArticleDOI
30 Apr 2020-Carbon
TL;DR: A review of the tensile properties of carbon nanotube reinforced aluminium matrix (Al-CNT) composites can be found in this article, where various processing routes for fabrication of AlCNT composites have been compared in terms of the resulting microstructure, degree of CNT dispersion, extent of interfacial reaction and its effect on the tensil properties.

118 citations

Journal ArticleDOI
TL;DR: In this article, a multiphase microstructure was developed in a V-bearing medium carbon microalloyed steel using a two-step cooling and annealing (TSCA) treatment following finish forging.
Abstract: In an attempt to improve fatigue and fracture resistance, a multiphase (ferrite–bainite–martensite) microstructure was developed in a V-bearing medium carbon microalloyed steel using a two-step cooling and annealing (TSCA) treatment following finish forging. The monotonic, cyclic stress–strain and low cycle fatigue behavior of this steel are reported. These results are compared with those of ferrite–pearlite and tempered martensite microstructures obtained by air cooling (AC) and quenching and tempering (Q&T), respectively. The tensile properties of the multiphase microstructure are superior to those of the ferrite–pearlite and the Q&T microstructures. Under cyclic loading, the ferrite–pearlite microstructure showed hardening at higher total strain amplitudes (≥0.7%) and softening at lower total strain amplitudes (<0.7%). The quenched and tempered and the ferrite–bainite–martensite (TSCA) microstructures displayed cyclic softening at all total strain amplitudes employed. Despite the cyclic softening, the ferrite–bainite–martensite structure was cyclically stronger than the ferrite–pearlite and the Q&T microstructures. Bilinearity in the Coffin–Manson plots was observed in Q&T and the multiphase TSCA conditions. An analysis of fracture surface provided evidence for predominantly ductile crack growth (microvoid coalescence and growth) in the ferrite–pearlite microstructure and mixed mode (ductile and brittle) crack growth in Q&T and the multiphase TSCA microstructures.

77 citations

Journal ArticleDOI
TL;DR: In this article, the authors used X-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy characterization techniques to identify the presence of nickel deposition on the carbon nanotubes (CNTs) and the degree of graphitization.

52 citations

Journal ArticleDOI
TL;DR: In this paper, a mutiphase microstructure was developed in a V-bearing medium carbon microalloyed (MA) steel through a two-step cooling process that was followed by an annealing treatment.
Abstract: To improve toughness and fatigue strength, a mutiphase (ferrite (F)–bainite (B)–martensite (M)) microstructure was developed in a V-bearing medium carbon microalloyed (MA) steel through a two-step cooling process that was followed by an annealing (two-step cooling and annealing (TSCA)) treatment In the present paper, the high cycle fatigue (HCF) response determined in terms of the endurance limit, long crack fatigue threshold (ΔKth), crack closure and fatigue crack growth rate (FCGR) in a material that has a multiphase microstructure is presented and compared with those of the same material with a ferrite–pearlite (F–P) and a tempered martensite (T–M) microstructure obtained by air-cooling (AC) and quenching and tempering (Q&T), respectively Long crack fatigue threshold (ΔKth) and crack closure were evaluated using a dynamic compliance (DYNACOMP) measurement technique The fatigue limit of the F–B–M and the T–M microstructures (∼400 MPa) was greater than that of the F–P microstructure (∼340 MPa) At load ratios less than 05, the threshold for long crack growth was lower for the F–B–M microstructure compared with that of the F–P microstructure This is attributed to the reduced roughness-induced crack closure (RICC) contribution to the threshold in the former multiphase microstructure A quantitative analysis of the near-threshold fracture surfaces validated the above conclusion Fatigue crack growth rate in the Paris regime was found to be independent of the microstructure but dependent on the load ratio

51 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the creep-fatigue interaction (CFI) behavior of 316LN stainless steel with varying nitrogen content (0.07, 0.14 and 0.22 ) at temperature of 873 K under strain-controlled fatigue tests with a tensile-hold period of 1, 13.3 and 30 min.

50 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a detailed account of these improvements, focusing specifically on microstructure evolution during processing, and expander expansion during the fabrication of dual-phase alloys.
Abstract: Dual-phase (DP) steel is the flagship of advanced high-strength steels, which were the first among various candidate alloy systems to find application in weight-reduced automotive components. On the one hand, this is a metallurgical success story: Lean alloying and simple thermomechanical treatment enable use of less material to accomplish more performance while complying with demanding environmental and economic constraints. On the other hand, the enormous literature on DP steels demonstrates the immense complexity of microstructure physics in multiphase alloys: Roughly 50 years after the first reports on ferrite-martensite steels, there are still various open scientific questions. Fortunately, the last decades witnessed enormous advances in the development of enabling experimental and simulation techniques, significantly improving the understanding of DP steels. This review provides a detailed account of these improvements, focusing specifically on (a) microstructure evolution during processing, (b) exp...

438 citations

Journal ArticleDOI
TL;DR: In this article, an optimized MgO-impregnated porous biochar was prepared using an integrated adsorption-pyrolysis method for absorption of phosphate, ammonium and organic matter (humate).

321 citations

Journal ArticleDOI
TL;DR: A comprehensive review of recent progress in TMP of AHSSs, with focus on the processing-microstructure-property relationships of the processed AHSS, is provided in this paper.

251 citations