Order hardening of MgO by large precipitated volume fractions of spinel particles

Hüther, Werner; Reppich, Bernd

doi:10.1016/0025-5416(79)90063-6

Cited by 31 publications

(7 citation statements)

References 12 publications

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“…In each equation: γAPB is the APB energy of the L12 phase; b is the Burger's vector; d * is the critical particle size; f is the volume fraction of particles; T is the line tension, taken to be equal to Gb 2 /2 for screw dislocations; A is a geometrical factor equal to 0.72 for spherical precipitates; G is the shear modulus of the material and w is a dislocation repulsion factor approximated to 1 following Hüther et al [34]. The γAPB was calculated using the Miodownik and Saunders approach [35,36] and the ThermoCalc software package coupled with the TTNi8 database.…”

Section: Equationmentioning

confidence: 99%

On the continuous and discontinuous precipitation of the L12 phase in Cu-Ni-Al alloys

et al. 2020

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L12 precipitate hardened Cu-Ni-Al alloys offer high strength, corrosion resistance and anti-biofouling properties, making them useful in marine engineering applications. Optimisation of their mechanical properties requires a full understanding of their complex precipitate nucleation and coarsening mechanisms. In this work, the microstructural characteristics and hardness of three Cu-Ni-Al alloys with compositions of Cu(95-x)NixAl5 (x = 5, 15, 25 at%) were investigated in the homogenised state and following heat treatments at 700˚C for 1, 10, 100 and 1000 hours. L12 precipitates were observed in the alloys containing ≥ 15 at% Ni. In these alloys, the L12 phase was found to precipitate via both continuous and discontinuous routes following all exposures at 700˚C. The coarsening behaviours of the continuous and discontinuous L12 distributions were characterised and correlated to measurements of hardness and lattice misfit. The alloys containing 15 and 25 at% Ni exhibited peak hardness after 1 h at 700˚C, which corresponded to average particle diameters of 30 nm, respectively. These results were rationalised through calculations of the change in the critical resolved shear stress associated with the transition from weakly to strongly coupled superpartial dislocations. The discontinuous reaction was observed to be led by L12 phase formation, which extended into the neighbouring grain, ahead of the reorientation front of the matrix.

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Section: Equationmentioning

confidence: 99%

On the continuous and discontinuous precipitation of the L12 phase in Cu-Ni-Al alloys

et al. 2020

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“…For both equations: APB denotes the APB energy of the L12 precipitates; b denotes the magnitude of the Burger's vector of the dislocations; d * describes the critical precipitate size; f the volume fraction of precipitates; T the line tension, which is taken to be equal to Gb 2 /2 for screw dislocations; A is a geometrical factor equal to 0.72 for spherical precipitates; G is the shear modulus of the material and w is a factor describing the dislocation repulsion and approximated to 1 following Hüther et al [36].…”

Section: Equation 2 Equationmentioning

confidence: 99%

The effect of heat treatment on precipitation in the Cu-Ni-Al alloy Hiduron® 130

Christofidou

Robinson

Mignanelli

et al. 2017

Materials Science and Engineering: A

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The effect of heat treatment on precipitation in the Cu-Ni-Al alloy Hiduron® 130 Cupronickel alloys, reinforced by L12 precipitates, offer a high strength, corrosion resistant and anti-bio fouling material for marine engineering applications. These alloys exhibit complex precipitate nucleation and growth mechanisms that must be fully understood in order to optimise the mechanical properties. In this work, the microstructural characteristics of the Cu-Ni-Al based alloy, Hiduron ® 130, have been assessed in the as-received condition and following 100-hour thermal exposures at 500, 600, 700 and 900˚C and after a two-stage exposure at 900˚C for 100hours followed by 500˚C for 100 hours. The L12 phase was observed to precipitate both discontinuously and continuously and its subsequent coarsening was characterised alongside measurements of the lattice misfit. The hardness of the alloy was found to decrease with increasing exposure temperature up to the L12 solvus and correlated with the evolution of the L12 precipitates, the alloy grain size and the fraction of the discontinuously formed L12 phase.

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“…where G is the shear modulus of the material, and w describes the repulsion between a pair of dislocations, which can be approximated to 1, as discussed in the work by Hüther et al [55] Calculations were performed with APB energies estimated using the Miodownik and Saunders method. [56] The fine scale of the precipitates meant that the precipitate size distribution and volume fraction were difficult to obtain experimentally (using etching techniques) without introducing significant stereological errors.…”

Section: Microstructurementioning

confidence: 99%

Microstructural Stability and Properties of New Nickel‐Base Superalloys with Varying Aluminium: Niobium Ratio

et al. 2023

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New nickel‐base superalloys with higher temperature capability are required for future, more efficient gas turbine engines. In designing such alloys, careful consideration is required of the elemental concentrations to ensure a suitable balance of properties is obtained. Herein, the phase equilibria and microstructural stability of new nickel‐base superalloys with varying Al:Nb ratio are assessed via long‐term thermal exposures at 700 °C. The alloys are analyzed using scanning and transmission electron microscopy, X‐ray diffraction, differential scanning calorimetry, and Vickers hardness testing, with the results rationalized through mechanical property predictions based on strong‐ and weak‐pair dislocation coupling mechanisms. The alloys are shown to have greater thermal stability than Inconel 718 and exhibit a pronounced hardening effect after thermal exposure. Herein, their ability for controlled age hardening and potential ease of processing is highlighted in the results.

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Order hardening of MgO by large precipitated volume fractions of spinel particles

Cited by 31 publications

References 12 publications

On the continuous and discontinuous precipitation of the L12 phase in Cu-Ni-Al alloys

On the continuous and discontinuous precipitation of the L12 phase in Cu-Ni-Al alloys

The effect of heat treatment on precipitation in the Cu-Ni-Al alloy Hiduron® 130

Microstructural Stability and Properties of New Nickel‐Base Superalloys with Varying Aluminium: Niobium Ratio

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