Characterization of fracture toughness and toughening mechanisms in Laves phase Cr 2 Nb based alloys

Xue, Yufei; Li, S.M.; Zhong, Hong; Fu, Hengzhi

doi:10.1016/j.msea.2015.04.077

Cited by 31 publications

(7 citation statements)

References 31 publications

(38 reference statements)

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“…Addition of a second phase: Besides the above-described attempts to improve the room-temperature fracture toughness of single-phase Laves phase materials, dual-phase alloys consisting of a Laves phase toughened by the addition of ductile precipitates such as soft metals is another concept. For example, toughening of C15 NbCr 2 Laves phase by introducing fine and uniformly distributed, ductile bcc-Nb or bcc-Cr particles was already suggested in 1990/1991 by Anton and Shah [627] and Takeyama and Liu [628], respectively, and this concept was pursued for the same system for a long time, see, for example, [629][630][631][632][633]. In NbCr 2 Laves phase fabricated by spark plasma sintering (SPS), trace amounts of Nb and Cr solid solutions are observed to distribute among the grain boundaries.…”

Section: Figure 28mentioning

confidence: 99%

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

2020

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Laves phases with their comparably simple crystal structure are very common intermetallic phases and can be formed from element combinations all over the periodic table resulting in a huge number of known examples. Even though this type of phases is known for almost 100 years, and although a lot of information on stability, structure, and properties has accumulated especially during the last about 20 years, systematic evaluation and rationalization of this information in particular as a function of the involved elements is often lacking. It is one of the two main goals of this review to summarize the knowledge for some selected respective topics with a certain focus on non-stoichiometric, i.e., non-ideal Laves phases. The second, central goal of the review is to give a systematic overview about the role of Laves phases in all kinds of materials for functional and structural applications. There is a surprisingly broad range of successful utilization of Laves phases in functional applications comprising Laves phases as hydrogen storage material (Hydraloy), as magneto-mechanical sensors and actuators (Terfenol), or for wear- and corrosion-resistant coatings in corrosive atmospheres and at high temperatures (Tribaloy), to name but a few. Regarding structural applications, there is a renewed interest in using Laves phases for creep-strengthening of high-temperature steels and new respective alloy design concepts were developed and successfully tested. Apart from steels, Laves phases also occur in various other kinds of structural materials sometimes effectively improving properties, but often also acting in a detrimental way.

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Section: Figure 28mentioning

confidence: 99%

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

2020

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“…Therefore, the introduction of a ductile phase into Laves phase-based materials is attractive to obtain a two-phase alloy, which may preferably balance the strength and fracture toughness, in both binary and ternary systems. 12) The mechanical properties of two-phase alloys are strongly dependent on the morphology, volume fraction and the orientation relationship (OR) of the second phase. 13) However, it is difficult to control the microstructure of two-phase alloys composed of Laves and ductile phases, especially in binary systems, because for almost all of the binary Laves systems, the two-phase microstructure is obtained by a eutectic reaction because many Laves phases are in equilibrium with the ductile BCC phase with a limited solid solubility, which is insufficient for the large volume fraction of Laves phase precipitation.…”

Section: Introductionmentioning

confidence: 99%

Laves Phase Precipitation Behavior and the Orientation Relationship with BCC in Cr–Mo–Nb System

Ikeda

Horiuchi

et al. 2018

Mater. Trans.

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The isothermal sections of the CrMoNb ternary phase diagram have been studied. The C15 NbCr 2 Laves precipitation behavior in three different alloys has been investigated in the CrMoNb ternary system. The orientation relationship (OR) of NbCr 2 in BCC matrix among BCC/ Laves two-phase alloys and Cr-rich BCC 1 /Mo-rich BCC 2 /Laves three-phase alloy is different at 1473 K; OR 1: (011) BCC // ð11 1Þ C15 , ½0 11 BCC // ½ 110 C15 and OR 2: ð 411Þ BCC // (111) C15 , ½0 11 BCC // ½ 110 C15 with low lattice mismatch are both observed in Cr-rich alloys #3 (74Cr16Mo10Nb) and #2 (50Cr30Mo20Nb). OR 3: (011) BCC // (111) C15 , ½ 11 1 BCC // ½01 1 C15 with a lattice mismatch relatively larger than that of OR 1 and OR 2 is only observed in alloy #2, which may be due to the presence of BCC 1 and BCC 2 interphases formed after BCC decomposition. Only discontinuous precipitation is observed at grain boundaries in Cr-lean alloy #1 (42Cr31Mo27Nb) without obvious OR between the BCC matrix and Laves phase.

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“…Refs. [16][17][18][19][20][21][22]), the development of the multiligament zone implies the existence of a rising crack growth resistance (R-curve) behavior in hardmetals [23][24][25][26][27], the size of which is dependent on the width and strength of the ligaments [7,24,28]; and thus, on the microstructural arrangement of the composites under consideration. R-curve behavior may be described as the ability of a microstructure to develop toughening mechanisms on an advancing crack, which can be done, for example, by screening the crack tip from the far-field driving force [21,29,30].…”

Section: Introductionmentioning

confidence: 99%

FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

Tarragó

Jiménez‐Piqué

Schneider

et al. 2015

Materials Science and Engineering: A

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Exceptional fracture toughness levels exhibited by WC-Co cemented carbides (hardmetals) are due mainly to toughening derived from plastic stretching of crack-bridging ductile enclaves. This takes place due to the development of a multiligament zone at the wake of cracks growing in a stable manner. As a result, hardmetals exhibit crack growth resistance (R-curve) behavior.In this work, the toughening mechanics and mechanisms of these materials are investigated by combining experimental and analytical approaches. Focused Ion Beam technique (FIB) and Field-Emission Scanning Electron Microscopy (FESEM) are implemented to obtain serial sectioning and imaging of crack-microstructure interaction in cracks arrested after stable extension under monotonic loading. The micrographs obtained provide experimental proof of the developing multiligament zone, including failure micromechanisms within individual bridging ligaments. Analytical assessment of the multiligament zone is then conducted on the basis of experimental information attained from FIB/FESEM images, and a model for the description of R-curve behavior of hardmetals is proposed. It was found that, due to the large stresses supported by the highly constrained and strongly bonded bridging ligaments, WC-Co cemented carbides exhibit quite steep but short R-curve behavior. Relevant strength and reliability attributes exhibited by hardmetals may then be rationalized on the basis of such toughening scenario.

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Characterization of fracture toughness and toughening mechanisms in Laves phase Cr 2 Nb based alloys

Cited by 31 publications

References 31 publications

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Laves Phase Precipitation Behavior and the Orientation Relationship with BCC in Cr–Mo–Nb System

FIB/FESEM experimental and analytical assessment of R-curve behavior of WC–Co cemented carbides

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