Multiscale modelling of precipitation hardening in Al–Cu alloys: Dislocation dynamics simulations and experimental validation

Santos-Güemes, R.; Bellón, B.; Esteban-Manzanares, G.; Segurado, J.; Capolungo, Laurent; LLorca, J.

doi:10.1016/j.actamat.2020.02.019

Cited by 89 publications

(33 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In practice, this is done by measuring the stress required to drive a dislocation line through the precipitate in MD simulations, after which A is adjusted in DDD to reproduce the result. A high value means simply an impenetrable precipitate [33]. It is also possible to use experimental input, e.g., high-resolution transmission electron microscopy measurements of the elastic fields of the precipitate, which can subsequently be used in DDD simulations [34].…”

Section: Methodsmentioning

confidence: 99%

Plastic yielding and deformation bursts in the presence of disorder from coherent precipitates

Salmenjoki

Lehtinen

Laurson

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

Alloying metals with other elements is often done to improve the material strength or hardness. A key microscopic mechanism is precipitation hardening, where precipitates impede dislocation motion, but the role of such obstacles in determining the nature of collective dislocation dynamics remains to be understood. Here, three-dimensional discrete dislocation dynamics simulations of fcc single crystals are performed with fully coherent spherical precipitates from zero precipitate density up to ρ p = 10 21 m −3 and at various dislocationprecipitate interaction strengths. When the dislocation-precipitate interactions do not play a major role, the yielding is qualitatively the same as for pure crystals, i.e., dominated by "dislocation jamming," resulting in glassy dislocation dynamics exhibiting critical features at any stress value. We demonstrate that increasing the precipitate density and/or the dislocation-precipitate interaction strength creates a true yield or dislocation assembly depinning transition, with a critical yield stress. This is clearly visible in the statistics of dislocation avalanches observed when quasistatically ramping up the external stress, and it is also manifested in the response of the system to constant applied stresses. The scaling of the yielding with precipitates is discussed in terms of the Bacon-Kocks-Scattergood relation.

show abstract

Section: Methodsmentioning

confidence: 99%

Plastic yielding and deformation bursts in the presence of disorder from coherent precipitates

Salmenjoki

Lehtinen

Laurson

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…The micro-hardness change trend of the matrix with exposure temperatures is showed in Figure 7 . The micro-hardness of the matrix is decreased from 114.5 HV to 85.3 HV once the T6 (235 °C) alloy is exposed to 250 °C for 100 h. Reported by Sui et al, this was mainly due to the coarsening of precipitate to decrease its precipitation strengthening effect [ 44 ]. The micro-hardness of the matrix is further reduced to 67.3 HV (300 °C for 100 h) and 62.5 HV (350 °C for 100 h).…”

Section: Discussionmentioning

confidence: 99%

Morphological Evolutions of Ni-Rich Phases in Al-Si Piston Alloys during 250–400 °C Thermal Exposure Processes

Geng

Bian

et al. 2020

Materials

View full text Add to dashboard Cite

The thermal stability of the Al-Si alloys during the thermal exposure process from 250 °C to 400 °C was systematically investigated. The relationships between the morphological evolution and the mechanical changes of the alloys were determined through the Vickers hardness test and materials characterization method. Initially, the alloys exhibited similar thermal degradation behavior. For example, the exposure process of the alloy at 300 °C can be divided into two stages according to the changes of the alloy hardness and the matrix micro-hardness. In detail, the first stage (0–2 h) exhibited a severe reduction of the alloy hardness while the second stage showed a more leveled hardness during the following 98 h. There are three identified morphological characteristics of Ni-rich phases in the alloy. Furthermore, the differences in both composition and the micro-hardness between these Ni-rich phases were confirmed. The underlying relationships between the morphological transformation of the Ni-rich phases and hardness fluctuation in the alloy were correlated and elucidated. The observed alloy hardness increase when the exposure temperature was 400 °C was unexpected. This behavior was explained from the perspectives of both Ni-rich phases evolution and dispersoid formation.

show abstract

“…According to the Orowan relationship (Figure 9), larger inter-particle spacing results in a decrease in the resistance to dislocation motion thereby facilitating the occurrence of Orowan looping. The increased deformability of the matrix via the easy dislocation motions leads to reduced strength and subsequently diminished quality index values in the castings [24][25][26][27][28][29][30]. Aging at lower temperature results in formation of precipitates; with fine sizes, high density and lower inter-particle spacing.…”

Section: Stage Imentioning

confidence: 99%

Generation and Relaxation of Residual Stresses in Automotive Cylinder Blocks

Mohamed¹,

Samuel²,

Doty³

et al. 2021

Advanced Applications of Hydrogen and Engineering Systems in the Automotive Industry

View full text Add to dashboard Cite

There is direct proportionality between ultimate tensile stress (UTS) and residual stresses (RS). Residual stresses gradually decrease with decreasing cooling/quenching rates. Quenching in cold water develops highest, whereas air cooling produces lowest, residual stresses. Significant increase in RS is observed in specimens with low dendrite arm spacing (high solidification rate), while lower residual stresses are measured in specimens with high dendrite arm spacing (low solidification rate). For I-4 and V-6 engine blocks, there is refinement in microstructure due to the increase in solidification rate along the cylinder length. The developed residual stresses are normally tensile in both engine types. Air cooling following solution heat treatment produces higher RS compared to warm water and cold water quenching. Solution heat treatment and freezing lead to maximum RS relaxation where 50% of the stresses are reduced after the solution heat treatment step. Aging time and temperature are directly proportional to the residual stresses relaxation. Relaxation of RS also depends on the geometry and size of the workpiece. It should be mentioned here that the I-4 and V-6 cylinder blocks were provided by Nemak-Canada (Windsor-Ontario-Canada). Residual stress measurements technique and procedure are typical of those used by the automotive industry in order to provide reliable data for industrial applications supported by intensive experiments.

show abstract

Multiscale modelling of precipitation hardening in Al–Cu alloys: Dislocation dynamics simulations and experimental validation

Cited by 89 publications

References 47 publications

Plastic yielding and deformation bursts in the presence of disorder from coherent precipitates

Plastic yielding and deformation bursts in the presence of disorder from coherent precipitates

Morphological Evolutions of Ni-Rich Phases in Al-Si Piston Alloys during 250–400 °C Thermal Exposure Processes

Generation and Relaxation of Residual Stresses in Automotive Cylinder Blocks

Contact Info

Product

Resources

About