Structural, elastic and electronic properties of θ (Al2Cu) and S (Al2CuMg) strengthening precipitates in Al–Cu–Mg series alloys: First-principles calculations

Zhang, J.; Yong, Hu; Mao, Chen; Peng, Ping

doi:10.1016/j.ssc.2012.09.003

Cited by 120 publications

(31 citation statements)

References 21 publications

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“…The load was applied in the vertical direction. The particle properties were assumed to be linearly elastic and isotropic with elastic modulus and Poisson's ratios found in literature [74] for the case of θ phase (Al2Cu, E = 120GPa)…”

Section: Discussionmentioning

confidence: 99%

Acoustic emission signal processing framework to identify fracture in aluminum alloys

Wisner

Mazur

Perumal

et al. 2019

Engineering Fracture Mechanics

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Acoustic emission (AE) is a common nondestructive evaluation tool that has been used to monitor fracture in materials and structures. The direct connection between AE events and their source, however, is difficult because of material, geometry and sensor contributions to the recorded signals. Moreover, the recorded AE activity is affected by several noise sources which further complicate the identification process. This article uses a combination of in situ experiments inside the scanning electron microscope to observe fracture in an aluminum alloy at the time and scale it occurs and a novel AE signal processing framework to identify characteristics that correlate with fracture events. Specifically, a signal processing method is designed to cluster AE activity based on the selection of a subset of features objectively identified by examining their correlation and variance. The identified clusters are then compared to both mechanical and in situ observed microstructural damage. Results from a set of nanoindentation tests as well as a carefully designed computational model are also presented to validate the conclusions drawn from signal processing.

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Section: Discussionmentioning

confidence: 99%

Acoustic emission signal processing framework to identify fracture in aluminum alloys

Wisner

Mazur

Perumal

et al. 2019

Engineering Fracture Mechanics

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“…The aluminium was used in the as‐received condition, which contains up to 5% Cu, 1.8% Mg, 1% Mn, 0.5% Fe, 0.5% Si, and trace amounts of Cr and Zn. The particles present in the aluminium were examined by energy‐dispersive spectroscopy; the chemical content was identified as primary particle types including Al 7 Cu 2 Fe, Al 2 CuMg, and Al 2 Cu, which agrees with related information in the literature …”

Section: Methodsmentioning

confidence: 99%

Progressive failure monitoring and analysis in aluminium by in situ nondestructive evaluation

Wisner

Potstada

Perumal

et al. 2019

Fatigue Fract Eng Mat Struct

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Damage initiation and progression in precipitate hardened alloys are typically linked to the failure of second phase particles that result from the precipitation process. These particles have been shown to be stress concentrators and crack starters as a result of both particle debonding and fracture. In this investigation, a precipitate hardened aluminium alloy (Al 2024‐T3) is loaded monotonically to investigate the role the particles have in the progressive failure process. The damage process was monitored continuously by combining the acoustic emission method either with in situ scanning electron microscopy or X‐ray microcomputed tomography to obtain both surface and volume microstructural information. Particles were observed to fracture only in the elastic regime of the material response, while void growth at locations predominantly near particles were found to be associated with progressive failure in the plastic region of the macroscopic response. Experimental findings were validated by fracture simulations at the scale of particle‐matrix interface.

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“…The RS would be expected to vary from grain to grain (as recently measured by μHD in [54]); (b) each grain is elastically anisotropic and this has not been accounted for here; (c) since the plastically affected depth spans below 30 μm depth consequently anisotropic micro slip bands could create intergranular stresses between the grains; (d) various crystalline phases with different elasticity are present, e.g. the Al 2 CuMg eutectic phase precipitates are twice as stiff as the Al-rich matrix [60], and these are not taken into account in RS estimates. Since the Al-rich grains are fairly isotropic (the Zener ratio is 1.2 [54]) thus (a) and (b) may have small impact on the RSs scatter (discussed in details in [54]).…”

Section: Sub-surface Residual Stress Measurement Between the Notchesmentioning

confidence: 99%

High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

et al. 2016

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The moderately high lateral RS gradients (on the order of tens of MPa/μm) near shot peened notches in conjunction with the shallow treatment depth (some hundreds of microns) limit the application of far-field and/or high resolution synchrotron diffraction residual stress measurement techniques. Recently proposed Focused Ion Beam -Scanning Elecron Microscope -Digital Image Correlation (FIB-SEM-DIC) based micro mechanical stress relaxation methods for the measurement of residual stress at the micron scale became suitable techniques for local evaluation of residual stresses and stress gradients in shot peened specimens. In this paper ultra-high resolution (~0.5-0.8 μm depth and 5-10 μm lateral resolution) mechanical relaxation stress measurements were used to evaluate the stress variation local to individual peening dimples in ceramic (60-120 μm diameter beads) shot peened Al-7075-T651 double notched samples having 0.15, 0.5 and 2.0 mm radii using Micro-Hole Drilling (μHD), Micro-Slot Cutting (μSC) and micro X-ray Diffraction (μXRD) methods. The micron-sized sampling volumes enabled the stress to be evaluated in individual impact craters (dimples) showing significant point-to-point variation (~+/−150 MPa) (with certain dimples even recording tensile stresses). After around 30 μm of layer removal the heavily deformed region had largely been removed and the stress profile became much more homogeneous. At this depth the μHD and μSC results were in good accord with those from μXRD measurements which sample over a much larger volume (~40 μm depth × 50 μm laterally) showing an in-plane compressive stress of around 150 MPa far from the notches with the residual stress rising to about 200 MPa at a blunt (2 mm) notch and 500 MPa for a sharp (0.15 mm) one. Further, these recorded variations of residual stresses were correlated with microstructural features, e.g. grains, networks of sub-surface cracks, intermetallics and highly deformed sub-surface regions, revealed by large volume Serial Sectioning Tomography using Plasma Xe + Focus Ion Beam -Scanning Electron Microscope (PFIB-SEM), EDS and EBSD maps. This allowed for the first time characterize large volume (100 × 66 × 30 μm 3 ) of shot peened regions with resolution of dozens of nanometers and correlate residual stress depth profiles with 3D microstructural features. Finally, in (Benedetti et al. 2016, Int. J. Fatigue) these RS measurements are used to reconstruct the RS field through finite element (FE) analyses.

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Structural, elastic and electronic properties of θ (Al2Cu) and S (Al2CuMg) strengthening precipitates in Al–Cu–Mg series alloys: First-principles calculations

Cited by 120 publications

References 21 publications

Acoustic emission signal processing framework to identify fracture in aluminum alloys

Acoustic emission signal processing framework to identify fracture in aluminum alloys

Progressive failure monitoring and analysis in aluminium by in situ nondestructive evaluation

High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

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