Chapter 53 Microscopy and plasticity of the L12 γphase

Veyssière, P.; Saada, G.

doi:10.1016/s1572-4859(96)80008-8

Cited by 65 publications

(56 citation statements)

References 203 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A different nonplanar core structure is exhibited by the ah110i superdislocation in Ni 3 (Al,Ta), in which the structure apparently forms via a cross slip process. The observed core structures are fully consistent with the Kear-Wilsdorf lock configuration that has been postulated to explain the anomalous temperature dependence of the yield and flow strengths in this and other compounds with the L1 2 structure (Kear and Wilsdorf, 1962;Veyssiere and Saada, 1996) Thin-foil effects are necessarily of concern for these HRTEM studies. These effects are potentially most significant for mixed dislocations, which will tend to incline in the thin foil-an effect confirmed by the EAM calculations for the 608 dislocation in aluminum.…”

Section: Discussionsupporting

confidence: 78%

“…A number of weak-beam TEM studies have been conducted indicating that the anomalous temperature dependence is associated with cross slip of the dissociated ah101i from octahedral to the cube cross slip system (for a review, see Veyssiere and Saada, 1996). The frictional stress is apparently larger on the {010} plane.…”

Section: Ah101i Screw Superdislocation In Ni 3 Almentioning

confidence: 99%

See 1 more Smart Citation

HRTEM of dislocation cores and thin‐foil effects in metals and intermetallic compounds

Mills

Baluc

Sarosi

2006

Microscopy Res & Technique

View full text Add to dashboard Cite

Examples of the observation and analysis of dislocation cores and dislocation fine structure in metals and intermetallics using high resolution transmission electron microscopy are discussed. Specific examples include the 60 degrees dislocations in aluminum, a011 edge dislocations in NiAl, and screw dislocations in Ni3Al. The effect of the thin TEM foils on the structure and imaging of these dislocations is discussed in light of embedded atom method calculations for several configurations and coupled with image simulations. Some generalizations based on these calculations are discussed. These analyses enables determination of the spreading or decomposition of the edge component of the cores, both in and out of the glide plane, which can have significant implications for the modeling of macroscopic behavior.

show abstract

Section: Discussionsupporting

confidence: 78%

Section: Ah101i Screw Superdislocation In Ni 3 Almentioning

confidence: 99%

HRTEM of dislocation cores and thin‐foil effects in metals and intermetallic compounds

Mills

Baluc

Sarosi

2006

Microscopy Res & Technique

View full text Add to dashboard Cite

show abstract

“…The higher strength of the γ' phase in AM1 as compared with MC-NG results from the increased levels of Ti and Ta which substitute for Al. Moreover, substitutions of Ti or Ta for Al in Ni 3 Al were reported to increase the APBE of this ordered phase [20] thus rendering more difficult the shearing of the γ' precipitates by pairs of matrix dislocations.…”

Section: Resultsmentioning

confidence: 99%

Influence of Chemistry on the Tensile Yield Strength of Nickel-Based Single Crystal Superalloys

Caron¹,

Diogolent²,

Drawin³

2011

AMR

View full text Add to dashboard Cite

Abstract. The tensile yield strength of AM1 and MC-NG single crystal superalloys with a γ' precipitate size close to 300 nm were compared within the 20-1050°C temperature range. The room temperature yield strength of the fourth generation MC-NG superalloy is about 200 MPa less than that of the AM1 first generation one. Inversely, at higher temperatures (T > 800°C), the tensile strength of MC-NG is higher than that of AM1. These results are discussed by taking into account the elementary deformation mechanisms and the respective strengths of the γ and γ' phases. Experiments on a modified MC-NG alloy show that reinforcing the γ' phase by increasing the contents of Ti and Ta is an efficient way to recover a higher tensile strength at low temperatures. Rhenium addition and increase of the γ' solvus temperature are suggested to be beneficial for the high temperature tensile strength. Data published on various other single crystals are in agreement with these hypotheses.

show abstract

“…Most models explain that the YSA in L1 2 intermetallics is caused by the exhaustion of the mobile dislocations on {010} planes by the Kear-Wilsdorf (K-W) locking mechanism [8][9][10][11][12][13][14]. The K-W locks are mainly caused by the cross-slip of the screw superdislocations [11,15,16].…”

Section: Introductionmentioning

confidence: 99%

Effects of Alloying Atoms on Antiphase Boundary Energy and Yield Stress Anomaly of L12 Intermetallics: First-Principles Study

Gao

Wang

et al. 2018

Crystals

View full text Add to dashboard Cite

Abstract:The antiphase boundary energies of {111} and {010} planes in L1 2 intermetallics (Ni 3 Ge, Ni 3 Si, Al 3 Sc, Ni 3 Al, Ni 3 Ga and Al 3 Ti) under different pressure are presented using first-principle methods. The yield stress anomaly is predicted by the energy criterion p-factor based on the anisotropy of antiphase boundary energies and elasticity. These L1 2 intermetallics exhibit anomalous yield stress behavior except Al 3 Sc. It is found that pressure cannot introduce the transition between anomalous and normal behavior. In order to investigate the transition, Al 3 Sc, Ni 3 Si and Ni 3 Ge with substituting atoms are investigated in detail due to p-factors of them are close to the critical value p c = √ 3. Al 3 Sc can change to anomalous when Sc atoms in {010} planes are substituted by Ti with plane concentration 25%. When Li substitutes Al in {111} planes, anomalous Al 3 Sc will change to normal. Ni 3 Si and Ni 3 Ge can exhibit normal yield stress behavior when Ge and Si in {111} planes are substituted by alloying atoms with plane concentrations 12.5% and 25%. When Ga and Al substitute in {010} planes, normal Ni 3 Si and Ni 3 Ge will revert to anomalous behavior. Therefore, transparent transition between normal and anomalous yield stress behavior in L1 2 intermetallics can be introduced by alloying atoms.

show abstract

Chapter 53 Microscopy and plasticity of the L12 γphase

Cited by 65 publications

References 203 publications

HRTEM of dislocation cores and thin‐foil effects in metals and intermetallic compounds

HRTEM of dislocation cores and thin‐foil effects in metals and intermetallic compounds

Influence of Chemistry on the Tensile Yield Strength of Nickel-Based Single Crystal Superalloys

Effects of Alloying Atoms on Antiphase Boundary Energy and Yield Stress Anomaly of L12 Intermetallics: First-Principles Study

Contact Info

Product

Resources

About