Anisotropy in Compression Creep-Ageing Behavior of 2219-T3 Aluminum Alloy

2021 ◽  
Vol 315 ◽  
pp. 31-36
Author(s):  
Xue Ying Chen ◽  
Li Hua Zhan ◽  
Hai Long Liao ◽  
Yuan Gao

Creep age forming technology (CAF) has been widely used to manufacture large integral panels in aerospace industry. However, due to the bending of the sheet metal, the stress states usually changes along the thickness direction during the CAF process, resulting in a complex distribution of stress. In addition, deformation texture is introduced when the sheet has a large pre-deformation, which also greatly affects the shape and performance of the component after aging. In this paper, the anisotropy in compression creep-ageing behavior of 2219-T3 aluminum alloy was studied. It was found that there is obvious anisotropy of compressive creep strains, the creep strain is the largest when the applied stress is along the rolling direction (RD) and the smallest when the applied stress is along the transverse direction (TD). The results of room temperature (25 ° C) and high temperature (165 ° C) tensile property test shows that the as-received material properties has obvious in-planar anisotropy, and the yield strength in the RD is the largest, but the 45° and TD are basically the same. Interestingly, the anisotropy of yield strength after SFA and compressive stress creep aging has basically disappeared, that is,the material properties tended to be isotropic after ageing.

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Osama M. Alyousif ◽  
Rokuro Nishimura

The environment-induced cracking (EIC) of aluminum alloy 5052-H3 was investigated as a function of applied stress and orientation (Longitudinal rolling direction—Transverse: LT and Transverse—Longitudinal rolling direction: TL) in 0.5 M sodium chloride solution (NaCl) using a constant load method. The applied stress dependence of the three parameters (time to failure;tf, steady-state elongation rate,Iss, and transition time at which a linear increase in elongation starts to deviate,tss) obtained from the corrosion elongation curve showed that these relationships were divided into three regions, the stress-dominated region, the EIC- dominated region, and the corrosion-dominated region. Aluminum alloy 5052-H3 with both orientations showed the same EIC behavior. The value oftss/tfin the EIC-dominated region was almost constant with0.57±0.02independent of applied stress and orientation. The fracture mode was transgranular for 5052-H3 with both orientations in the EIC-dominated region. The relationships between logIssand logtffor 5052-H3 in the EIC-dominated region became a good straight line with a slope of −2 independent of orientation.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 954
Author(s):  
Hailong Wang ◽  
Wenping Deng ◽  
Tao Zhang ◽  
Jianhua Yao ◽  
Sujuan Wang

Material properties affect the surface finishing in ultra-precision diamond cutting (UPDC), especially for aluminum alloy 6061 (Al6061) in which the cutting-induced temperature rise generates different types of precipitates on the machined surface. The precipitates generation not only changes the material properties but also induces imperfections on the generated surface, therefore increasing surface roughness for Al6061 in UPDC. To investigate precipitate effect so as to make a more precise control for the surface quality of the diamond turned Al6061, it is necessary to confirm the compositions and material properties of the precipitates. Previous studies have indicated that the major precipitate that induces scratch marks on the diamond turned Al6061 is an AlFeSi phase with the composition of Al86.1Fe8.3Si5.6. Therefore, in this paper, to study the material properties of the AlFeSi phase and its influences on ultra-precision machining of Al6061, an elastoplastic-damage model is proposed to build an elastoplastic constitutive model and a damage failure constitutive model of Al86.1Fe8.3Si5.6. By integrating finite element (FE) simulation and JMatPro, an efficient method is proposed to confirm the physical and thermophysical properties, temperature-phase transition characteristics, as well as the stress–strain curves of Al86.1Fe8.3Si5.6. Based on the developed elastoplastic-damage parameters of Al86.1Fe8.3Si5.6, FE simulations of the scratch test for Al86.1Fe8.3Si5.6 are conducted to verify the developed elastoplastic-damage model. Al86.1Fe8.3Si5.6 is prepared and scratch test experiments are carried out to compare with the simulation results, which indicated that, the simulation results agree well with those from scratch tests and the deviation of the scratch force in X-axis direction is less than 6.5%.


2016 ◽  
Vol 879 ◽  
pp. 454-458 ◽  
Author(s):  
Jia Qi Duan ◽  
Md Zakaria Quadir ◽  
Michael Ferry

Microstructure and texture evolution of commercially pure Ni processed by accumulative roll-bonding (ARB) up to eight cycles were studied using electron back scattered diffraction (EBSD). During ARB processing, the original coarse equiaxed grains were gradually transformed into refined lamellar grains along the rolling direction (RD). Shear bands started forming after three cycles. The fraction of low angle grain boundaries (LAGBs) increased after the first and second cycle because of orientation spreading within the original grains. However, their fraction decreased with the evolution of high angle grain boundaries (HAGBs) during subsequent deformations, until saturation was reached after six cycles. Overall, the typical deformation texture components (S, Copper and Brass) were enhanced up to six ARB cycles and then only Copper was further strengthened. At higher cycles a higher Copper concentration was found near sample surface than the interiors due to a high frictional shear of ARB processing.


2000 ◽  
Vol 646 ◽  
Author(s):  
Haruyuki Inui ◽  
Koji Ishikawa ◽  
Masaharu Yamaguchi

ABSTRACTEffects of ternary additions on the deformation behavior of single crystals of MoSi2 with the hard [001] and soft [0 15 1] orientations have been investigated in compression and compression creep. The alloying elements studied include V, Cr, Nb and Al that form a C40 disilicide with Si and W and Re that form a C11b disilicide with Si. The addition of Al is found to decrease the yield strength of MoSi2 at all temperatures while the additions of V, Cr and Nb are found to decrease the yield strength at low temperatures and to increase the yield strength at high temperatures. In contrast, the additions of W and Re are found to increase the yield strength at all temperatures. The creep strain rate for the [001] orientation is significantly lower than that for the [0 15 1] orientation. The creep strain rate for both orientations is significantly improved by alloying with ternary elements such as Re and Nb.


Author(s):  
Jana S. De Wet ◽  
Eileen Africa ◽  
Ranel Venter

Ballet dancers are exposed to chronic high training and performance demands that are associated with overtraining syndrome and injury. Balancing high training loads with recovery to reduce the risk of negative training adaptations is critical. Moreover, the recovery-stress states of professional ballet dancers during training phases of a season are largely unknown. Professional dancers (n = 27) from one classical ballet company in South Africa were monitored for two 8-week phases of a ballet season. A recovery-stress questionnaire for Athletes (RESTQ-76 Sport) was completed weekly during the rehearsal phase (P1) and the performance phase (P2), which took place at the start and the end of the ballet season, respectively. Comparisons were calculated between phases, sexes, and levels of performance with a mixed-model ANOVA and between demographic variables with a one-way ANOVA. The performance phase was signified by lower total recovery (TR, p < 0.01) and higher total stress (TS, p < 0.01) for the group. Female dancers had significantly lower recovery scores than male dancers during P2 (p < 0.01). No differences between levels of performance were found. Subscales previously associated with overreaching and injury were identified in certain groups during P2. In conclusion, P2 was a critical period where dancers, especially females, experienced high stress and low recovery. This could increase the risk for injury and negative training adaptations.


Author(s):  
Swaminathan Ganesan ◽  
Sampath Vedamanickam

In this study, the influence of upper cycle temperature (maximum temperature in a cycle) and the magnitude of applied stress on the functional properties of an SMA during partial thermomechanical cycling has been studied. A near-equiatomic NiTi SMA was chosen and tested under different upper cycle temperatures (between martensite finish (Mf) and austenite finish (Af) temperatures) and stress level (below and above the yield strength of the martensite). The upper cycle temperature was varied by controlling the magnitude of the current supply. The results show that a raise in the upper cycle temperature causes the permanent strain to increase and also lowers the stability. However, decreasing the stress imposed to a value lower than the yield strength of the martensite improves cyclic stability. The upper cycle temperature was found to influence the crack nucleation, whereas the applied stress level the crack propagation during partial thermomechanical cycling of SMAs. Therefore, decreasing the upper cycle temperature as well as the magnitude of stress applied to lower than the yield stress of martensite have been found to be suitable strategies for increasing the lifespan of SMA-based actuators during partial thermomechanical cycling.


2009 ◽  
Vol 374 (1-2) ◽  
pp. 96-105 ◽  
Author(s):  
Chandra Vemavarapu ◽  
Madhu Surapaneni ◽  
Munir Hussain ◽  
Sherif Badawy

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 98 ◽  
Author(s):  
Zhengyang Kang ◽  
Yonghong Fu ◽  
Xingyu Fu ◽  
Martin Jun

In recent years, surface texturing in micro-scale has been attempted on the surface of cutting tools for multiple purposes, e.g., cutting force reduction, prolonging life-span, anti-adhesion, etc. With respect to machinability and performance, micro-groove texture (MGT) has dominated in this field compared to other textured patterns. In this study, a novel volcano-like texture (VLT) was fabricated on the rake face of cemented carbide inserts (WC-Co, YG6) by fiber laser. The following cutting experiment tested the flat, MGT and VLT tools in turning aluminum alloy 6061. The effects of coolant and cutting conditions were investigated. In addition, a validated FEM model was employed to explore the distribution of stress and temperature fields in the tool-chip interface. The initial forming process of adhesion layer on rake face was investigated as well. The results indicated that lower cutting force and less adhesion can be achieved by small scale VLT. This study not only introduced VLT on cutting tools but also revealed its comprehensive performance.


Author(s):  
Alessandro Valgimigli ◽  
Enrico Bertocchi ◽  
Alberto Lazzarini ◽  
Luca D’agostino ◽  
Luca Splendi

The strong competition of the automotive market brings the industries to look continuously for more challenging comfort and performance standards. These requirements often contrast with the need for weight reduction related to the restrictive emissions limits. In this scenario, the investments aimed at increasing the structure efficiency (stiffness-to-weight ratio) become fundamental. The objective of this work is to propose a methodology that allows to identify the most important chassis areas in terms of efficiency: the design and research efforts could then be focused on the real determinant parts. This is done through a sensitivity process that works on frame subsystems and then on each component, first varying the material properties and then the thickness (and so the mass). The designing loadcases considered are the torsional stiffness, bending stiffness, modal analysis and frequency response analysis. The results show which are the most important subsystems and components that affects the chassis efficiency and that will have to be re-designed in order to improve the current architecture.


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