Distortion and Residual Stress in Quenched Aluminum Bars

Becker, Richard; Karabin, M.E.; Liu, J. C.; Smelser, Ronald

doi:10.1115/1.2823352

Cited by 32 publications

(26 citation statements)

References 7 publications

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“…These gradients cause inhomogeneous plastic flow to occur, which in turn produces distortion and residual stresses. [1,2] For a rectilinear block like those investigated here, immediately after quenching tensile plastic strains occur initially at the rapidly cooling edges of the material. The plastic zone then expands to cover all the rapidly cooling surfaces.…”

Section: Introductionmentioning

confidence: 99%

The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

Robinson

Tanner

Truman

et al. 2012

Materials Characterization

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The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010.

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Section: Introductionmentioning

confidence: 99%

The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

Robinson

Tanner

Truman

et al. 2012

Materials Characterization

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show abstract

“…One of the first descriptions of the magnitude of the residual stresses in heat treatable aluminium alloys was provided by Kleint and Janney 1 . More recently Becker,Karabin et al 2 quantified both the residual stresses and subsequent distortion for aluminium alloy bars when water quenching. For a rectilinear block like those investigated here, immediately after quenching tensile plastic strains occur initially at the rapidly cooling edges of the material.…”

Section: Introductionmentioning

confidence: 99%

Influence of quenching and aging on residual stress in Al–Zn–Mg–Cu alloy 7449

Robinson

Tanner

Petegem

et al. 2012

Materials Science and Technology

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This investigation aimed to quantify the size and distribution of residual stresses remaining in rectilinear aluminium forged alloy blocks after they had been partially and fully heat treated. Various quench conditions were used including water at different temperatures and poly oxyethylene glycol (PAG) in two concentrations. The influence of standard and novel aging procedures including retrogression and reaging has been determined. Residual stresses were characterised using x-ray and neutron diffraction. Residual stress magnitudes were found to vary significantly with rapidity of cooling from the solution treatment temperature with the subsequent aging treatments having a much smaller effect. The influence of the heat treatments on mechanical properties of the alloy was predicted by means of quench factor analysis and measured using indentation hardness and tensile testing. Quench factor analysis is also used to predict the change in lattice parameter arising from different quench paths in the strain free reference samples (d 0 ).

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“…The residual stress distributions are too complex to be measured by techniques such as layer removal [3] and crack compliance [4,5] that can only measure 1-D through-thickness stress variations. The forgings are too large for practical measurement using neutron diffraction [6,7].…”

Section: Introductionmentioning

confidence: 99%

Quenching and Cold-Work Residual Stresses in Aluminum Hand Forgings: Contour Method Measurement and FEM Prediction

Prime

Newborn²,

Balog³

2003

MSF

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Abstract. The cold-compression stress relief process used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings does not fully relieve the stresses. This study measured and predicted the residual stress in 7050-T74 (solution heat treated, quenched, and artificially overaged) and 7050-T7452 (cold compressed prior to aging) hand forgings. The manufacturing process was simulated by finite element analysis. First, a thermal analysis simulated the quench using appropriate thermal boundary conditions and temperature dependent material properties. Second, a structural analysis used the thermal history and a temperature and strain-rate dependent constitutive model to predict the stresses after quenching. Third, the structural analysis was continued to simulate the multiple cold compressions of the stress relief process. Experimentally, the residual stresses in the forgings were mapped using the contour method, which involved cutting the forgings using wire EDM and then measuring the contour of the cut surface using a CMM. Multiple cuts were used to map different stress components. The results show a spatially periodic variation of stresses that results from the periodic nature of the cold work stress relief process. The results compare favorably with the finite element prediction of the stresses.

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Distortion and Residual Stress in Quenched Aluminum Bars

Cited by 32 publications

References 7 publications

The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

Influence of quenching and aging on residual stress in Al–Zn–Mg–Cu alloy 7449

Quenching and Cold-Work Residual Stresses in Aluminum Hand Forgings: Contour Method Measurement and FEM Prediction

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