ACHIEVING ULTRAFINE GRAIN SIZE IN Mg-Al-Zn ALLOY BY COLD DRAWING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 927-933 ◽  
Author(s):  
HONGYING CHAO ◽  
YANG YU ◽  
ERDE WANG
Keyword(s):  
Grain Size ◽  
Strain Hardening ◽  
Grain Refinement ◽  
Annealing Temperature ◽  
High Strength ◽  
Cold Drawing ◽  
Ultrafine Grain ◽  
Area Reduction ◽  
Ultrafine Grain Size ◽  
Cold Area

Ultrafine-grain size of ~1µm was achieved in an AZ31B Mg alloy wires with high strength prepared by cold drawing and subsequent annealing in the present study. Effects of cold-drawn area reduction (CAR) on strain hardening, recrystallized grain refinement and annealing temperature were investigated. The results showed that the maximum cold area reduction as high as 65.1% could be reached at room temperature, which resulted in the notable strain hardening, grain refinement and the decrease of annealing temperature.

Strategy for Achieving High Strength in Al-Mg-Sc Alloys by Intense Plastic Straining

2012 ◽  
Vol 706-709 ◽  
pp. 55-60 ◽  
Author(s):  
Rustam Kaibyshev ◽  
Anna Mogucheva ◽  
Andrii Dubyna
Keyword(s):  
Grain Size ◽  
Strain Hardening ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
High Strength ◽  
Necessary Condition ◽  
Angular Pressing ◽  
Strength Increment ◽  
Hardened Condition

It is shown that implementation of high strains through equal-channel angular pressing (ECAP) and/or rolling into alloys belonging to Al-Mg-Sc-Zr system allows achieving high strength and satisfactory ductility. It was shown that strain hardening gives a main contribution to overall strength increment attributed to intense plastic straining; the role of grain size hardening is minor. However, extensive grain refinement is a necessary condition for retaining sufficient ductility in full-hardened condition for these materials.

SPD-Induced Grain Boundary Segregations and Superior Strength in UFG Al Alloys

2010 ◽  
Vol 667-669 ◽  
pp. 665-669
Author(s):  
Nariman A. Enikeev ◽  
Maxim Yu. Murashkin ◽  
Xavier Sauvage ◽  
Vil U. Kazykhanov ◽  
Ruslan Valiev
Keyword(s):  
Grain Size ◽  
Atom Probe Tomography ◽  
Room Temperature ◽  
High Strength ◽  
Atom Probe ◽  
Mean Value ◽  
Al Alloys ◽  
Ultrafine Grain ◽  
Ultrafine Grain Size ◽  
Grain Boundary Segregations

Two Al alloys (AA1570 and AA6061) in the solutionized state have been processed by HPT at room temperature to achieve a homogeneous UFG structure. After HPT, the grain size was found to have a mean value about 100 nm for both alloys. Measured yield stress values of HPT-produced UFG alloys being plotted in terms of the Hall-Petch relationship were found to exceed the plot predictions for the range of ultrafine grain size. For both alloys, Atom Probe Tomography measurements allowed to reveal segregation of solute elements along grain boundaries. The origin of the extremely high strength of the alloys nanostructured by HPT is discussed with a special attention to the influence of such segregations on the emission and the mobility of dislocations.

scholarly journals Mechanical properties, deformation and fracture mechanisms of bimodal Cu under tensile test

2021 ◽  
Vol 60 (1) ◽  
pp. 15-24
Author(s):  
Silu Liu ◽  
Yonghao Zhao
Keyword(s):  
Yield Strength ◽  
Grain Refinement ◽  
Volume Fraction ◽  
Shear Fracture ◽  
High Strength ◽  
Tensile Specimen ◽  
Deformation Mechanisms ◽  
Fracture Mechanisms ◽  
Fracture Angle ◽  
Area Reduction

Abstract Metals with a bimodal grain size distribution have been found to have both high strength and good ductility. However, the coordinated deformation mechanisms underneath the ultrafine-grains (UFGs) and coarse grains (CGs) still remain undiscovered yet. In present work, a bimodal Cu with 80% volume fraction of recrystallized micro-grains was prepared by the annealing of equal-channel angular pressing (ECAP) processed ultrafine grained Cu at 473 K for 40 min. The bimodal Cu has an optimal strength-ductility combination (yield strength of 220 MPa and ductility of 34%), a larger shear fracture angle of 83∘ and a larger area reduction of 78% compared with the as-ECAPed UFG Cu (yield strength of 410 MPa, ductility of 16%, shear fracture angle of 70∘, area reduction of 69%). Grain refinement of recrystallized micro-grains and detwinning of annealing growth twins were observed in the fractured bimodal Cu tensile specimen. The underlying deformation mechanisms for grain refinement and detwinning were analyzed and discussed.

The Effects of Free Space in Mould Cavity on Sandglass Extrusion

2005 ◽  
Vol 475-479 ◽  
pp. 2999-3002
Author(s):  
W.L. Lu ◽  
Y. Wang ◽  
Jin Tao Hai
Keyword(s):  
Grain Size ◽  
Free Space ◽  
Large Strain ◽  
Experimental Results ◽  
Experimental Result ◽  
Ultrafine Grain ◽  
Theory Analysis ◽  
Ultrafine Grain Size ◽  
Mould Cavity

Sandglass extrusion is an ultrafine grain size method. Due to the repetitive and multiple extrusions, large strain will be accumulated and ultafine grain size can be obtained. There are some factors that can affect the experimental result of sandglass extrusion. Among these factors, free space in mould cavity is very important, which can affect the forming of the fold during the extrusion. In this paper, the effects of free space in mould cavity on sandglass extrusion have been discussed and theory analysis and experimental results have been reported.

DEVELOPMENT OF CRYSTALLOGRAPHIC TEXTURE AND GRAIN REFINEMENT IN THE ALUMINUM LAYER OF CU-AL-CU TRI-LAYER COMPOSITE DEFORMED BY EQUAL CHANNEL ANGULAR EXTRUSION

2012 ◽  
Vol 05 ◽  
pp. 325-334 ◽  
Author(s):  
B. TOLAMINEJAD ◽  
A.KARIMI TAHERI ◽  
M. SHAHMIRI ◽  
H. ARABI
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Cell Formation ◽  
Single Layer ◽  
Ultrafine Grain ◽  
Aluminum Layer ◽  
Dislocation Interaction ◽  
Copper Aluminum ◽  
Copper Composite

The present research is concerned with the aluminum layer of a loosely packed tri-layer copper-aluminum-copper composite deformed by ECAE process. Electron back scattered diffraction (EBSD), transmission electron microscope, and X-ray technique were employed to investigate the detailed changes occurring in the microtexture, microstructure (cell size and misorientation), and dislocation density evolution during consecutive passes of ECAE process performed on the composite based on route Bc. According to tensile test results, the yield stress of the aluminum layer was increased significantly after application of ECAE throughout the four repeated passes and then slightly decreased. An ultrafine grain size within the range of 500-600 nm was obtained in the Al layer by increasing the thickness of copper layers. It was observed that the reduction of grain size in the aluminum layer is nearly 57% more than that of an ECAE-ed single layer aluminum billet. Also, the grain refinement of the aluminum layer is accelerated throughout 8 passes. This observation was attributed to the higher rate of dislocation interaction, cell formation and texture development during the ECAE of the composite compared to those of the single billet.

Effect of Strain-Hardening Induced Grain Refinement on Springback in Microtube Press Bending Process

2012 ◽  
Vol 528 ◽  
pp. 111-118
Author(s):  
Cho-Pei Jiang
Keyword(s):  
Grain Size ◽  
Strain Hardening ◽  
Grain Refinement ◽  
Microstructure Development ◽  
Bending Angle ◽  
The Press ◽  
Bending Process ◽  
Twin Band ◽  
Three Stages ◽  
Springback Behavior

Seamless stainless microtube (SUS 304L) was selected for a detailed investigation of the strain-hardening influencing grain refinement and microstructural evolution during processing by varying press bending angles. The problem was approached in three stages. First, the microtubes were annealed to examine the initial grain size and analyzed the effect of grain size on mechanical properties by performing a tensile test. Second, a microtube press bending system was developed to observe springback behavior. Third, the microstructure of the microtube with different press bending angle was observed to investigate the effect of strain-hardening induced grain refinement on springback behavior. As a result, the occurrence of grain refinement reduced the springback amount. The mechanism of microstructure development in the shear zone during the press bending process is needle like, twin band and equiaxed and small rounded grains sequentially.

Microstructure and Mechanical Properties Resulting from Cold Rolling of Equal Channel Angular Extruded Commercial Purity Copper

2006 ◽  
Vol 503-504 ◽  
pp. 733-738
Author(s):  
A. Krishnaiah ◽  
Chakkingal Uday ◽  
P. Venugopal
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Cold Rolling ◽  
Equal Channel Angular Extrusion ◽  
Pure Copper ◽  
Ultrafine Grain ◽  
Ultrafine Grain Size ◽  
Ultrafine Grained ◽  
Angular Extrusion ◽  
Initial Processing

Equal channel angular extrusion (ECAE) is a processing method for introducing an ultrafine grain size into a material. In the present study, a two-step severe plastic deformation process was used to produce ultrafine grained copper with significantly enhanced strength. Equal channel angular extrusion was first used to refine the grain size of copper samples. The copper samples were further processed by cold rolling (CR) to a strain of 0.67 (about 50% reduction). This two-step process produced ultrafine grained copper with strengths higher than those of pure copper processed through ECAE only. This paper reports the microstructures and mechanical properties of the copper specimens processed by a combination of room temperature ECAE and CR. The effectiveness of initial processing by ECAE prior to cold rolling is discussed.

The Effect of Process Route on the Mechanical Properties and Microstructure Aluminum Al-Si-Cu-Mg-Mn Alloys

2020 ◽  
Vol 402 ◽  
pp. 67-72
Author(s):  
Rahmawaty ◽  
Surya Dharma ◽  
Abdul Razak ◽  
Sarjianto ◽  
Nisfan Bahri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Solution Treatment ◽  
Hardness Test ◽  
Optical Microscope ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Process Route ◽  
Ultrafine Grain Size

Equal-channel angular pressing (ECAP) is an effective fabrication process to modify ultrafine grain size. It is believed that the smaller grain size could improve the mechanical properties. In the present work, the solution treatment applied to Al-Si-Cu-Mg-Mn alloy. Furthermore, two models of ECAP have been done through one-to-three pass at room temperature. The microstructures were observed by optical microscope (OM) and scanning electron microscope (SEM). The micro-hardness of longitudinal plane was analyzed by vickers hardness test. The strength of ECAP materials at room temperature was obtained by using tensile test. The results show that the ECAP process has improved mechanical properties of alloys, which were the hardness and ultimate tensile strength tend to increase since single pass stage.

Sign in / Sign up

Export Citation Format

Share Document