Residual-stress-induced grain growth of twinned grains and its effect on formability of magnesium alloy sheet at room temperature

Kim, Se Jong; Kim, Dae-Yong; Lee, Keunho; Cho, Hoon-Hwe; Han, Heung Nam

doi:10.1016/j.matchar.2015.09.007

Cited by 16 publications

(2 citation statements)

References 23 publications

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“…For example, a combination of tensile residual stresses with service stresses adversely affects the fatigue life of the components, whereas compressive residual stresses are beneficial for improving the fatigue life of formed components [6,7]. Furthermore, depending on the nature of the residual stresses, they can cause an early onset of the plastic deformation or postpone yielding [8]. They are also a source of geometric deviations for the plastically formed components [9].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of the Influence of Process Parameters in Incremental Sheet Metal Forming on Residual Stresses

Maqbool

Bambach�

2019

JMMP

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The aim of this study is to analyze the co-relation between the geometrical accuracy of parts formed by single-point incremental forming (SPIF) and the resulting distribution of the residual stresses induced in the material as a function of the different process parameters of the SPIF process. The study was performed for a pyramidal frustum manufactured by varying the process parameters of SPIF, i.e., tool diameter, tool step-down, and wall-angle. The hole-drilling strain gage method was used to determine the residual stresses in the manufactured pyramids. Further, small strips were laser cut from the pyramids, and the curvature of the strips was measured. The curvature of the strips is a result of the intensity and distribution of the residual stresses, which in turn depends on the selected values of the process parameters. A validated numerical model of SPIF was used to determine the residual stresses parallel and perpendicular to the direction of tool motion at the center of a strip cut from the numerical model in clamped, unclamped, and trimmed states. Further, the change in the bending moment of a strip that occurred upon unclamping and trimming was calculated. Experimental and numerical investigations reveal that the most significant parameter in residual stress build-up and the reduction of geometrical accuracy is the wall angle. Upon unclamping, the highest change in the residual stresses and bending moment occurred with the largest tool step-down and tool diameter. Upon trimming, the magnitude of the residual stresses and bending moment changed the most with the largest tool step-down in both directions, whereas the change was highest with the smallest tool diameter in the transverse direction of the tool motion. Furthermore, upon trimming, the geometric deviations were highest with the large wall angles in the transverse direction of the tool motion. Overall, the effect of changing process parameters on the residual stress state and geometrical accuracy was more pronounced in the transverse direction of the tool motion.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of the Influence of Process Parameters in Incremental Sheet Metal Forming on Residual Stresses

Maqbool

Bambach�

2019

JMMP

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“…Such stress, in turn, results in significant lattice distortion and the creation of a multitude of dislocations. With an increase in immersion time, the stored internal strain energy continues to grow, providing the impetus for dislocation movement [23].…”

Section: Effect Of Dct On Grain Structurementioning

confidence: 99%

Effect on microstructure and mechanical properties of friction stir welded 5A06 aluminum alloy joints by deep cryogenic treatment

Du,

Qiao,

Wang

et al. 2024

Mater. Res. Express

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In order to improve the comprehensive mechanical properties of the welded joints of the 5A06 aluminum alloy, friction stir welded (FSW) joints were subjected to deep cryogenic treatment (DCT). The microstructure and mechanical properties were characterised using metallographic microscopy, X-ray diffractometer (XRD), energy spectrometer, microhardness tests, and tensile tests. The experimental results show that DCT refines the structure significantly due to the large temperature difference. This refinement results from an increase in Mg atoms within the α-Al solid solution through the precipitation of Al atoms, forming the Al3Mg2 phase. This enhancement in plasticity is achieved through dispersion distribution. Moreover, as the treatment time of DCT increases, the mechanical properties of the welded joint also improve significantly. With an extended treatment time of DCT, the microhardness of the welded joints reaches its peak, leading to an average microhardness increase of up to 6.9% compared to welded joints without DCT. Additionally, the tensile properties of the welded joints reach 385.3MPa, marking a 7.4% increase in tensile strength compared to joints without DCT. These experimental results underscore the significant impact of DCT on improving the welded joints.

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Effect of Residual Stress on the Continuous Cooling Transformation of High‐Strength Low‐Alloy Hot‐Rolled Strip

Fei,

Zhao,

Xue

2023

steel research int.

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The external stress will change the transformation process and microstructure of the material, and the residual stress generated during the processing of the material will also affect the transformation. Herein, the effect of residual stress is simulated by applying uniaxial elastic loads during the continuous cooling of high‐strength low‐alloy hot‐rolled strip. The transformation process and microstructure of the samples under different stress conditions are investigated. The results show that residual stress can accelerate the transformation process, and the tensile stress is greater than the compressive stress. The degree of lattice mismatch in stressed samples is larger than that in unstressed samples, leading to dislocation proliferation. It is found that there is a phenomenon of residual stress‐induced grain growth according to the statistics of grain size of different samples. Due to the higher dislocation density and smaller curvature of the parent phase interface under compressive stress, the compressive stress samples have a higher nucleation rate, resulting in smaller grain size than the tensile stress samples. In addition, the transformation texture also changes under residual stress.

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Residual-stress-induced grain growth of twinned grains and its effect on formability of magnesium alloy sheet at room temperature

Cited by 16 publications

References 23 publications

Experimental and Numerical Investigation of the Influence of Process Parameters in Incremental Sheet Metal Forming on Residual Stresses

Experimental and Numerical Investigation of the Influence of Process Parameters in Incremental Sheet Metal Forming on Residual Stresses

Effect on microstructure and mechanical properties of friction stir welded 5A06 aluminum alloy joints by deep cryogenic treatment

Effect of Residual Stress on the Continuous Cooling Transformation of High‐Strength Low‐Alloy Hot‐Rolled Strip

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