The microstructure of precipitation-hardened alloys

Martin, J.W.

doi:10.1016/b978-0-7506-3885-2.50006-2

Cited by 34 publications

(50 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Formation of precipitates from a supersaturated solid solution and their ability to block crystallographic slip was proposed as the reason for the increase in strength [3][4][5]. In 1937 the precipitates were detected experimentally for the first time by Guinier and Preston using x-ray diffraction and the precipitates were named Guinier-Preston, GP, zones [6].…”

mentioning

confidence: 99%

“…Coherency strengthening is used to model the strength contribution from shearable precipitates, in accordance with eq. 11 [5,53], where k coh is a constant between three strained misfit parameter. When the precipitates are looped by and four and ε the con dislocations their strength contribution is given by the Orowan equation (eq.…”

mentioning

confidence: 99%

“…When the precipitates are looped by and four and ε the con dislocations their strength contribution is given by the Orowan equation (eq. 12) [5,88], where ν α is Poisson's ratio of the α-Al matrix.…”

mentioning

confidence: 99%

See 2 more Smart Citations

The heat treatment of Al–Si–Cu–Mg casting alloys

Sjölander

Seifeddine

2010

Journal of Materials Processing Technology

460

223

View full text Add to dashboard Cite

Environmental savings can be made by increasing the use of aluminium alloys in the automotive industry as the vehicles can be made lighter. Increasing the knowledge about the heat treatment process is one task in the direction towards this goal. The aim of this work is to investigate and model the heat treatment process for Al-Si casting alloys. Three alloys containing Mg and/or Cu were cast using the gradient solidification technique to achieve three different coarsenesses of the microstructure and a low amount of defects.Solution treatment was studied by measuring the concentration of Mg, Cu and Si in the α-Al matrix using wavelength dispersive spectroscopy (WDS) after various times at a solution treatment temperature. A diffusion based model was developed which estimates the time needed to obtain a high and homogenous concentration of alloying elements for different alloys, temperatures and coarsenesses of the microstructure. It was shown that the yield strength after artificial ageing is weakly dependent on the coarseness of the microstructure when the solution treatment time is adjusted to achieve complete dissolution and homogenisation.The shape and position of ageing curves (yield strength versus ageing time) was investigated empirically in this work and by studying the literature in order to differentiate the mechanisms involved. A diffusion based model for prediction of the yield strength after different ageing times was developed for Al-Si-Mg alloys. The model was validated using data available in the literature. For Al-Si-Cu-Mg alloys further studies regarding the mechanisms involved need to be performed.Changes in the microstructure during a heat treatment process influence the plastic deformation behaviour. The Hollomon equation describes the plastic deformation of alloys containing shearable precipitates well, while the Ludwigson equation is needed when a supersaturated solid solution is present. When non-coherent precipitates are present, none of the equations describe the plastic deformation well. The evolution of the storage rate and recovery rate of dislocations was studied and coupled to the evolution of the microstructure using the Kocks-Mecking strain hardening theory.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

The heat treatment of Al–Si–Cu–Mg casting alloys

Sjölander

Seifeddine

2010

Journal of Materials Processing Technology

460

223

View full text Add to dashboard Cite

show abstract

“…The mechanical properties of extruded products are largely dependent on alloying elements present in solid solution. These elements increase the strength mainly through solid solution or precipitation hardening [13]. During casting of aluminum alloys, a large fraction of alloying elements segregate to the liquid and result in an inhomogeneous distribution of alloying elements.…”

Section: Application Of Homogenization Treatmentmentioning

confidence: 99%

Microstructural Evolution During the Homogenization of Al-Zn-Mg Aluminum Alloys

Eivani¹,

Zhou²,

Duszczyk³

2011

Recent Trends in Processing and Degradation of Aluminium Alloys

View full text Add to dashboard Cite

“…The yield stress due to dislocation looping,  loop , is inversely proportional to the channel width, l, which can then be formulated as a function of d and f leading to the following expression [23,24,29]:…”

Section: Relative Influence Of Precipitates' Yield Strength On Da/dtmentioning

confidence: 99%

Relative Contributions of Secondary and Tertiary γ' Precipitates to Intergranular Crack Growth Resistance in IN100 Alloy

Maciejewski¹,

Ghonem²

2012

Superalloys 2012 (Twelfth International Symposium)

View full text Add to dashboard Cite

This paper examines the role of secondary and tertiary ' on intergranular crack growth rate in P/M IN100. A series of different heat treatments were carried out on the as received material to vary the ' statistics (size and volume fraction) through control of the different features of the heat treatment cycle. Dwell fatigue crack growth experiments have been performed on as received as well as heat treated specimens at 650°C and 700°C in air with dwell time loading cycles. Results on the as-received material show that the intergranular crack growth rate while temperature dependent, is independent of the hold time period. For the modified microstructures tested at 650°C, the dwell crack growth rate is shown to be sensitive to ' variations. Considering that the yield strength of the continuum is a function of ' statistics, the role of ' on intergranular cracking was illustrated by correlating the crack growth rate and the continuum yield strength. This inverse relationship is examined numerically by modelling the grain boundary fracture path as an interface surrounded by near and far field continuum regions represented by viscoplastic flow formulations. Results of the model show that an increase in the continuum yield strength is accompanied by a lower viscous strain, resulting in higher constraint on the grain boundary sliding and thus, a decrease in the crack growth rate. This observation was further examined by calculating the individual components of yield strength associated with tertiary and secondary ' precipitates. These components were correlated with the crack growth rate, showing higher sensitivity to the tertiary ' precipitate hardening effects.

show abstract

The microstructure of precipitation-hardened alloys

Cited by 34 publications

References 13 publications

The heat treatment of Al–Si–Cu–Mg casting alloys

The heat treatment of Al–Si–Cu–Mg casting alloys

Microstructural Evolution During the Homogenization of Al-Zn-Mg Aluminum Alloys

Relative Contributions of Secondary and Tertiary γ' Precipitates to Intergranular Crack Growth Resistance in IN100 Alloy

Contact Info

Product

Resources

About

The microstructure of precipitation-hardened alloys

Cited by 34 publications

References 13 publications

The heat treatment of Al–Si–Cu–Mg casting alloys

The heat treatment of Al–Si–Cu–Mg casting alloys

Microstructural Evolution During the Homogenization of Al-Zn-Mg Aluminum Alloys

Relative Contributions of Secondary and Tertiary &gamma;' Precipitates to Intergranular Crack Growth Resistance in IN100 Alloy

Contact Info

Product

Resources

About

Relative Contributions of Secondary and Tertiary γ' Precipitates to Intergranular Crack Growth Resistance in IN100 Alloy