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Prithviraj Mukhopadhyay

Bio: Prithviraj Mukhopadhyay is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Alloy & Diamond. The author has an hindex of 4, co-authored 6 publications receiving 90 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, large size D711 synthetic single crystal diamonds are vacuum brazed with medium carbon steel using a Ni-Cr-Fe-B-Si alloy and inherent difficulties are critically investigated.

56 citations

Journal ArticleDOI
TL;DR: In this article, two active brazing alloys, i.e., Ni-Cr-B-Si-Fe and Ag-Cu-Ti, were used to braz synthetic diamond grits on a medium carbon steel substrate under a high vacuum environment.
Abstract: A multi-point brazed diamond tool requires high wear resistance of bonding alloy and strength of the brazed joint. In this work, two active brazing alloys, i.e., Ni-Cr-B-Si-Fe and Ag-Cu-Ti were used for brazing synthetic diamond grits on a medium carbon steel substrate under a high vacuum environment. The performance of the brazed joints was subsequently investigated and compared. The microstructure of the filler alloys was found to play a key role in influencing the bond wear characteristics, grit-alloy interfacial chemistry and strength of the brazed joint. Formation of Cu4Ti compounds in Ag-Cu-Ti alloy and boride and silicide compounds in case of Ni-Cr alloy contributed to the enhancement of hardness of the alloys. The bond wear characteristics of Ni-Cr alloy were substantially superior to that of Ag-Cu-Ti alloy. A single grit test of the brazed samples was carried out to investigate the failure pattern of the brazed joints. Ni-Cr brazed joints predominantly failed at the bond level. The residual stress and microstructural flaws in the form of microcracks at alloy-grit interface of the as-brazed test samples led to such a failure. In contrast, no such crack was detected in the case of Ag-Cu-Ti alloy and the joints failed by ductile fracture of alloy near to the interface, leading to diamond pull out. The present study elucidates the differences in wear, strength of bond and failure pattern of the brazed joints in the light of alloy and interfacial microstructure.

46 citations

Journal ArticleDOI
TL;DR: In this paper, micro-Al2O3 ceramic reinforcements were found to be uniformly distributed in the microstructure of the modified filler material, which showed a tendency to get clustered, impairing the improvement in abrasion resistance property of the primary filler alloy.

28 citations

Journal ArticleDOI
TL;DR: In this article, a cubic cubic boron nitride (cBN) surface was melted on cBN surface and interfacial reaction phases were probed, and only nitrides and borides of Ti were detected but without any Zr-based product.

10 citations

Journal ArticleDOI
TL;DR: In this paper, a single-layer diamond dresser was developed by high vacuum brazing technology using Ni-Cr and Ag-Cu-2Ti alloy and the vacuum level was maintained in the range of 10−6−10−7mbar.
Abstract: In the current work, multipoint single layer brazed diamond dressers were indigenously developed by high vacuum brazing technology using Ni-Cr and Ag-Cu-2Ti alloy. The vacuum level was maintained in the range of 10−6–10−7 mbar. To assess the quality, the developed dressers were subjected to eight dressing cycles with increasing grit penetration depth. The Ag-Cu-2Ti alloy, possessing a lower liquidus temperature of 820 °C, showed a superior grit retention ability compared to Ni-Cr alloy, having a higher liquidus temperature of 1050 °C. Higher thermal residual stresses developed in the case of Ni-Cr alloy, due to higher brazing temperature and difference in Young’s moduli and the coefficient of thermal expansion of the diamond grit, filler alloy, unfavorably led to the premature bond level failure of brazed diamond grit under lower specific loads. Elevated brazing temperature and formation of unfavorable intermetallic phases were found impairing the effectiveness of Ni-Cr alloy and caused severe graphitization of diamond. On the other hand, the silver-based bond experienced a potential threat of rapid wear by the hard bond-abrasive system of the grinding wheel during dressing. Localized “scooping” of bond material was observed in Ag-based bond layer securing diamond grits. Through a separate pin-on-disc test, it was demonstrated that this alloy received a substantial wear rate of 3.364 mm3/min and exhibited deterioration of frictional behavior, despite the presence of silver. The Ag-Cu-2Ti alloy with lower brazing temperature and lower tendency of graphitization has otherwise a more promising scope but only if the composition is suitably altered to bring in significantly higher abrasion resistance in its mechanical characteristics.

4 citations


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Journal ArticleDOI
TL;DR: Brazing is a 5000-year-old joining process which still meets advanced joining challenges today as mentioned in this paper, where components are joined by heating above the melting point of a filler metal placed between them.
Abstract: Brazing is a 5000-year-old joining process which still meets advanced joining challenges today. In brazing, components are joined by heating above the melting point of a filler metal placed between...

62 citations

Journal ArticleDOI
01 Nov 2019-Carbon
TL;DR: In this article, the effects of alloying elements Cr, B, and Si on the interfacial bonding strength and adhesive transfer of brazed diamond with Ni-Cr-B-Si filler alloy by first-principles calculations and experiments were investigated.

52 citations

Journal ArticleDOI
TL;DR: In this paper, the interface reaction and solidified microstructure in AISI 1045 steel and diamond grit joints brazed using a commercial Ni-Cr-P filler alloy were systematically studied at a typical brazing temperature of 950 °C.
Abstract: Active brazing is a promising technique for the fabrication of high-performance diamond abrasive tools, which is especially beneficial to the manufacturing of hard-to-machine materials such as ceramics and high-strength metals. Ni-Cr based filler alloys are commonly used to fabricate diamond abrasive tools under different brazing strategies. However, in the previous studies brazing conditions are inconsistent, and the mechanisms of the interface reaction and the microstructure evolution in the synthetic diamond and Ni-Cr-P filler alloy reaction system are not well understood. In this work, the interface reaction and solidified microstructure in AISI 1045 steel and diamond grit joints brazed using a commercial Ni-Cr-P filler alloy were systematically studied at a typical brazing temperature of 950 °C. A rapid formation of both Cr3C2 and Cr7C3 compounds was observed at the very early stage of liquid-solid reaction. An anomalous delamination of Cr7C3 and formation of primary (Ni,Cr)5P2 dendrites and FeNi3 phase in near-eutectic Ni-P matrix were observed after extended brazing reaction. Moreover, the effect of brazing time on the residual thermal stresses, and hence the integrity of brazed synthetic diamond, were experimentally revealed and discussed with the implications for the fabrication of diamond abrasive tools.

41 citations

Journal ArticleDOI
TL;DR: In this article, a series of filler metals and brazing methods for diamond tools are reviewed systematically, and the fracture modes and stress distribution issues are considered as the major reliability concern.

35 citations

Journal ArticleDOI
TL;DR: In this paper, ultrasonic-assisted induction brazing of diamond grits onto 1045 steel with Ni-Cr-B-Si-Fe was investigated and compared with those obtained by the conventional induction brasings.

32 citations