scholarly journals Simultaneously Enhanced Strength and Ductility of Al–Mg–Si Alloys during Aging Process Induced by Electro-Pulsing Treatment

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1383
Author(s):  
Yitong Wang ◽  
Yuguang Zhao ◽  
Xiaofeng Xu ◽  
Dong Pan ◽  
Wenqiang Jiang ◽  
...  
Keyword(s):  
Mechanical Treatment ◽  
Mobile Dislocation ◽  
Metallic Materials ◽  
Mobile Dislocation Density ◽  
Dislocation Glide ◽  
Quantitative Calculation ◽  
Novel Technology ◽  
Element Simulation ◽  
Microscopy Characterization ◽  
Strength And Ductility

Most methods used for strengthening metallic materials, such as thermal-mechanical treatment, will sacrifice the ductility. A novel technology, electric pulsing treatment (EPT), is applied to break this trade-off, which produces an Al–Mg–Si alloy with superior ductility and higher strength within only 560 ms. Systematic electron microscopy characterization and finite element simulation reveal that EPT promotes the formation of clusters Mg2(Si,Cu)3 and sub-grain boundaries. The results of quantitative calculation indicate that the dislocation entanglement is delayed due to the existence of clusters and longer dislocation glide distance, so that ultimate strength is fully improved. Moreover, the superior ductility is mainly governed by sub-grains which lead to higher mobile dislocation density, appearance of new crystal orientations, and prevention of crack propagation. Thereupon, this interesting finding paves the way in developing the Al–Mg–Si alloy with higher mechanical properties efficiently.

The creation rate of mobile dislocation density in a creep experiment

1986 ◽  
Vol 20 (8) ◽  
pp. 1075-1078 ◽  
Author(s):  
J.A. Montemayor-Aldrete ◽  
J. Soullard ◽  
R. Gómez-Ramírez ◽  
A. Calles
Keyword(s):  
Dislocation Density ◽  
Mobile Dislocation ◽  
Mobile Dislocation Density ◽  
Creep Experiment ◽  
The Creation ◽  
Creation Rate

The Influence of Mobile Dislocation Density on the Fracture Toughness of B2-Based Ni-Fe-Al Alloys

1994 ◽  
Vol 350 ◽  
Author(s):  
A. Misra ◽  
R. D. Noebe ◽  
R. Gibala
Keyword(s):  
Fracture Toughness ◽  
Dislocation Density ◽  
Tensile Ductility ◽  
Growth Direction ◽  
Mobile Dislocation ◽  
Second Phase ◽  
Mobile Dislocation Density ◽  
Dislocation Generation ◽  
Multiphase Materials ◽  
Β Phase

AbstractThe deformation and fracture behaviors of two directionally solidified multi-phase Ni-Fe-Al ordered alloys were investigated. One alloy consisted of continuous β+γ lamellae with fine γ precipitates within the γ phase. The NiAl-based β phase of this alloy exhibited <100> slip even when deformed parallel to the [001] growth direction. This material exhibited an initiation fracture toughness of ∼ 30 MPa √m and tensile ductility of 10%. The second alloy consisted of aligned but discontinuous γ lamellae within a continuous β phase. Again, the γ phase contained γ precipitates, but unlike the previous alloy, the β phase also contained a fine dispersion of bcc precipitates due to spinodal decomposition. The β phase of this alloy deformed by <111> slip. This four-phase alloy exhibited a fracture toughness of ∼ 21 MPa √m and tensile ductility of 2%. Observations of the plastic zone in both alloys indicated significant plasticity in the β phase due to easy slip transfer from the ductile second phase. The enhanced fracture resistance of these multiphase materials compared to single phase β alloys is attributed in large part to intrinsic toughening of the β phase by an increased mobile dislocation density due to efficient dislocation generation from the β/γ interfaces.

Finite Element Simulation of Aluminum ECAP Material Flow

2013 ◽  
Vol 423-426 ◽  
pp. 267-270
Author(s):  
Jian Hui Li ◽  
Zu Jian Yu ◽  
Da Zhi Xiao ◽  
Li Ping Zhang
Keyword(s):  
Finite Element ◽  
Material Flow ◽  
Maximum Principal Stress ◽  
Metallic Materials ◽  
Rigid Plastic ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Fine Grain ◽  
Corner Flow ◽  
Element Simulation

To enhancing strength and toughness of metals, severe plastic deformation (SPD) grain refinement was a typical method. As one of the SPD method, equal channel angular pressing is an effective method in fabricating ultra-fine grain metallic materials. In this paper, the rigid-plastic finite element method was used to analyze the aluminum alloy ECAP processing, to reveal the material flow character and its effect on microstructure evolution. The simulation results were agreed with plastic mechanics and experiment well, and it was shown that distribution of maximum principal stress was not uniform, material located at the front-end of sample flow easily and material located at the top of die channel corner flow difficultly.

Joining by forming of polymer-metal sheet-tube connections

2020 ◽  
Vol 234 (7) ◽  
pp. 938-946
Author(s):  
Luis M Alves ◽  
Rafael M Afonso ◽  
Paulo AF Martins
Keyword(s):  
Adhesive Bonding ◽  
Dissimilar Materials ◽  
Metal Sheet ◽  
Test Cases ◽  
Metallic Materials ◽  
Element Simulation ◽  
New Process ◽  
Polymer Metal ◽  
Polymer Tube ◽  
Main Operating

This paper focuses on the mechanical joining of sheets to tubes made from dissimilar materials. The objective is to investigate the applicability of deformation-assisted joining by annular sheet squeezing to hybrid polymer-metal connections in order to understand how this new process can be used as an alternative to conventional fastening and adhesive bonding. The presentation draws from identification of the main operating parameters and modes of deformation to characterisation of the process workability limits. Selected test cases retrieved from experimentation and finite element simulation are included. The work is an extension of the previous work of the authors on metallic materials, and results show that joining by annular sheet squeezing is an easy and effective solution to connect a metal sheet to a polymer tube away from its end.

A consideration of mobile dislocation density

1978 ◽  
Vol 12 (9) ◽  
pp. 753-757 ◽  
Author(s):  
S. Raghuraman ◽  
R.J. Arsenault
Keyword(s):  
Dislocation Density ◽  
Mobile Dislocation ◽  
Mobile Dislocation Density
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