Nanostructured Dual Phase Ti-Al through Consolidation of Particles by Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 63-68
Author(s):  
Edward W. Lui ◽  
Wei Xu ◽  
Kenong Xia
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Multiple Scales ◽  
Bulk Material ◽  
Dual Phase ◽  
Two Phase ◽  
Angular Pressing

A two-phase Ti-Al material was fabricated by severe plastic deformation. Particles of finely mixed elemental Ti and Al were mechanically milled and then consolidated by equal channel angular pressing. The bulk material has a unique interpenetrating structure of Ti and Al phases with multiple scales from micro to nano. Compared to its coarse structured counterpart, the multiscale structured material exhibited a significant increase in strength without compromising plasticity.

Equal Channel Angular Pressing and Torsion of Pure Al Powder in Tubes

2010 ◽  
Vol 97-101 ◽  
pp. 1109-1115 ◽  
Author(s):  
Xiao Xi Wang ◽  
Ke Min Xue ◽  
Ping Li ◽  
Zhan Li Wu ◽  
Qi Li
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Bulk Material ◽  
Full Density ◽  
Powder Materials ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Al Powder ◽  
Set Up

In this work, a new severe plastic deformation technique for preparing bulk fine-grained materials has been developed to achieve higher plasticity of powder materials. This novel technique, named Equal Channel Angular Pressing and Torsion (ECAPT), combines two severe plastic deformation methods: equal channel angular pressing and twist extrusion. With the designed ECAPT set-up, pure Al powder particles were successfully consolidated into full dense bulk material with fine grains at a lower deformation temperature (200°C) by Powder in Tubes-Equal Channel Angular Pressing and Torsion (PITS-ECAPT). After two passes of PITS-ECAPT, the microstructures at X, Y and Z planes of each sample were all sheared and elongated along a certain direction with fine banded structures; the grains were greatly squashed and refined with an average grain size of ~ 11.90µm; the deformed sample reached the full density; the micro-hardness and yield strength achieved 49.9kg/mm2 and 155Mpa respectively, which were significantly higher than those of as-cast annealed pure Al and pure Al powder sintered materials.

scholarly journals Biocomposites Produced from Hardwood Particles by Equal Channel Angular Pressing Without Additives

2019 ◽  
Vol 3 (2) ◽  
pp. 36
Author(s):  
Yu Bai ◽  
Xiaoqing Zhang ◽  
Kenong Xia
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Crack Formation ◽  
Cell Deformation ◽  
Processing Conditions ◽  
Ongoing Research ◽  
Angular Pressing ◽  
Wood Particles

Equal channel angular pressing (ECAP) has been shown to be a promising method for producing biocomposites from wood particles. However, severe plastic deformation during ECAP would cause considerable cracking when consolidation is carried out without a binder. In this study, the processing conditions were investigated for ECAP of hardwood particles into bulk biocomposites without any additives. Crack formation and wood cell deformation were examined in conjunction with thermal stability and crystallinity of the biocomposites. In comparison with hot pressing without severe shearing, a decrease in crystallinity and severe deformation of wood cells occurred during ECAP. Improved processability and homogeneous deformation would occur at high ECAP temperature (e.g., 210 °C) or low ECAP speed (e.g., 10 mm/min), leading to reduced crack formation in the ECAP-produced biocomposites. Despite its tendency to cause periodic cracking, effective plastic deformation in the regions between cracks was shown to improve interparticle binding. Ongoing research points to the potential achievement of crack-free hardwood (HW) consolidated without a binder, leading to significantly enhanced strength.

Influence of Experimental Environment on the Enhancement of Ultra Fine Grain Structure with Optimum Ductility of Equal Channel Angular Pressed Copper

2014 ◽  
Vol 592-594 ◽  
pp. 410-415
Author(s):  
A.T. Vijayashakthivel ◽  
T.N. Srikantha Dath ◽  
B. Ravishankar
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Bulk Material ◽  
Grain Structure ◽  
Structural Refinement ◽  
High Deformation ◽  
Die Geometry ◽  
Angular Pressing ◽  
Fine Grain ◽  
Increased Strength

Strengthening the engineering material through Severe Plastic Deformation and associated structural refinement is an established practice. Among the Severe Plastic Deformation process, Equal Channel Angular Pressing (ECAP) assumes a significant place. In this, it is possible to attain even ultra fine grain (UFG) structure through high deformation in bulk material working mode. However ECAPed material suffers lack of ductility, structural inhomogenity and even thermodynamically unstable structure, as evidenced in the published literature on ECAP of copper. The present study on ECAP of commercial purity copper aimed to attain a structure of higher hardness by shedding little ductility is deviated from the past work; in this, commercial quality copper is ECAPed at 3000 C with a die geometry channel angle of 1100 and corner angle of 200 necessitating less local/working stress. During certain number of passes (six passes), the material experiences higher hardness with fair amount of ductility. The material does not exhibit any further strengthening beyond six passes, which is possibly due to dislocations annihilation/recovery. The increased strength and loss of ductility of the material results in degrading the material when it undergoes tenth pass.

Grain Refinement of Vanadium by Low Temperature Severe Plastic Deformation

2010 ◽  
Vol 638-642 ◽  
pp. 1934-1939 ◽  
Author(s):  
Y.B. Chun ◽  
S.H. Ahn ◽  
D.H. Shin ◽  
S.K. Hwang
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Low Temperature ◽  
Yield Strength ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Tensile Elongation ◽  
Lamellar Microstructure ◽  
Lamellar Thickness ◽  
Angular Pressing

Recent advances in the severe plastic deformation technique have shown that effective refinement of the microstructure can be achieved in pure metals as well as in alloys. Among the various methods of severe plastic deformation, equal channel angular pressing has been the subject of numerous research works. Since the grain refining effect of this technique appears to reach a peak at a level of approximately 200 nm further microstructural changes are sought—deformation at a cryogenic temperature being one of the candidate routes. In the present study, we opted to combine equal channel angular pressing and low temperature plastic deformation to refine the microstructure of commercially pure V. The starting microstructure consisted of equiaxed grains with an average size of 100 micrometers. This microstructure was refined to a 200 nm thick lamellar microstructure by 8 passes of equal channel angular pressing at 350°C. The lamellar thickness was further reduced to 140 nm upon subsequent cryogenic rolling, which resulted in room temperature yield strength of 768 MPa. In the specimens, recrystallization annealed at 850°C, the grain size reached 1000 nm or larger, and the yield strength obeyed the Hall-Petch relationship with that grain size. The tensile elongation value, which was low and insensitive to the grain size in the as-deformed state, increased significantly up to 43% with the recrystallization annealing.

scholarly journals Effect Of Severe Plastic Deformation On Microstructure Evolution Of Pure Aluminium

2015 ◽  
Vol 60 (2) ◽  
pp. 1437-1440 ◽  
Author(s):  
B. Leszczyńska-Madej ◽  
M.W. Richert ◽  
M. Perek-Nowak
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Subgrain Size ◽  
Bulk Material ◽  
Extrusion Process ◽  
Hydrostatic Extrusion ◽  
Pure Aluminium ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cumulative Strain

AbstractProcesses of severe plastic deformation (SPD) are defined as a group of metalworking techniques in which a very large plastic strain is imposed on a bulk material in order to make an ultra-fine grained metal. The present study attempts to apply Equal-Channel Angular Pressing (ECAP), Hydrostatic Extrusion (HE) and combination of ECAP and HE to 99.5% pure aluminium. ECAP process was realized at room temperature for 16 passes through route Bc using a die having an angle of 90°. Hydrostatic extrusion process was performed with cumulative strain of 2.68 to attain finally wire diameter of d = 3 mm. The microstructure of the samples was investigated by means of transmission and scanning electron microscopy. Additionally, the microhardness was measured and statistical analysis of the grains and subgrains was performed. Based on Kikuchi diffraction patterns misorientation was determined. The measured grain/subgrain size show, that regardless the mode of deformation process (ECAP, HE or combination of ECAP and HE processes), grain size is maintained at a similar level – equal to d = 0.55-0.59μm. A combination of ECAP and HE has achieved better properties than either single process and show to be a promising procedure for manufacturing bulk UFG aluminium.

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