Bimodal grain-structure formation in a Co–Cr-based superalloy during ultrahigh-homologous-temperature annealing without severe plastic deformation

2019 ◽  
Vol 783 ◽  
pp. 173-178 ◽  
Author(s):  
Cheng-Lin Li ◽  
Jeong Mok Oh ◽  
Jong-Taek Yeom ◽  
Chan Hee Park
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structure Formation ◽  
Grain Structure ◽  
Homologous Temperature

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

Gradient Structure Formation by Severe Plastic Deformation

2006 ◽  
pp. 787-792
Author(s):  
M. Danylenko ◽  
V. Gorban ◽  
Yu.N. Podrezov ◽  
S.A. Firstov ◽  
O. Rosenberg ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structure Formation ◽  
Gradient Structure

Nanocrystalline structure formation in Al-Mg-Sc alloys during severe plastic deformation

2006 ◽  
Vol 2006 (6) ◽  
pp. 533-540 ◽  
Author(s):  
S. V. Dobatkin ◽  
V. V. Zakharov ◽  
A. Yu. Vinogradov ◽  
K. Kitagawa ◽  
N. A. Krasil’nikov ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structure Formation ◽  
Nanocrystalline Structure

Finite Element Simulation of Heat Transfer during Cryogenic Asymmetric Sheet Rolling of Aluminum Alloys

2016 ◽  
Vol 716 ◽  
pp. 692-699 ◽  
Author(s):  
Alexander Pesin ◽  
Denis Pustovoytov
Keyword(s):  
Heat Transfer ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Grain Structure ◽  
Sheet Rolling ◽  
Fine Grain ◽  
Element Simulation ◽  
Alloy 6061

Aluminum and its alloys are widely used as structural materials in aerospace, automotive and other industries due to low density and high specific strength. Efficient way to increase strength and other properties of aluminum alloys is to form an ultra fine grain structure using severe plastic deformation methods. Cryogenic asymmetric sheet rolling under liquid nitrogen temperature is a process of severe plastic deformation that can be used to improve the aluminum alloys structure and properties. Prediction of sheet temperature during plastic deformation is very important. The temperature of sheet is changed due to the conversion of mechanical work of deformation into heat through sliding on contact surfaces. This paper presents the results of the finite element simulation of heat transfer during cryogenic asymmetric sheet rolling of aluminum alloy 6061. The effect of thickness reduction, rolling velocity and friction coefficient on the deformation heating and temperature field of aluminum alloy 6061 was found. The results of investigation could be useful for the development of the optimal treatment process of aluminum alloys by cryogenic severe plastic deformation to obtain the ultra fine grain structure and high strength properties.

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.

Cellular Automaton Simulation of Microstructure Evolution for Friction Stir Blind Riveting

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Avik Samanta ◽  
Ninggang Shen ◽  
Haipeng Ji ◽  
Weiming Wang ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Numerical Approach ◽  
Dislocation Dynamics ◽  
Grain Structure ◽  
Workpiece Material ◽  
Friction Stir ◽  
Ca Model

Friction stir blind riveting (FSBR) process offers the ability to create highly efficient joints for lightweight metal alloys. During the process, a distinctive gradient microstructure can be generated for the work material near the rivet hole surface due to high-gradient plastic deformation and friction. In this work, discontinuous dynamic recrystallization (dDRX) is found to be the major recrystallization mechanism of aluminum alloy 6111 undergoing FSBR. A cellular automaton (CA) model is developed for the first time to simulate the evolution of microstructure of workpiece material during the dynamic FSBR process by incorporating main microstructure evolution mechanisms, including dislocation dynamics during severe plastic deformation, dynamic recovery, dDRX, and subsequent grain growth. Complex thermomechanical loading conditions during FSBR are obtained using a mesh-free Lagrangian particle-based smooth particle hydrodynamics (SPH) method, and are applied in the CA model to predict the microstructure evolution near the rivet hole. The simulation results in grain structure agree well with the experiments, which indicates that the important characteristics of microstructure evolution during the FSBR process are well captured by the CA model. This study presents a novel numerical approach to model and simulate microstructure evolution undergoing severe plastic deformation processes.

scholarly journals Influence of special features of the gradient structure formation during severe plastic deformation of alloys with different types of a crystalline lattice

2019 ◽  
Vol 17 (1) ◽  
pp. 64-75 ◽  
Author(s):  
Georgy I. Raab ◽  
Ilyas S. Kodirov ◽  
Gennady N. Aleshin ◽  
Arseniy G. Raab ◽  
Nikolai K. Tsenev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Structure Formation ◽  
High Pressure Torsion ◽  
Crystalline Lattice ◽  
Gradient Structure ◽  
Temperature Range ◽  
Deformation Treatment

Problem Statement (Relevance): The paper describes some features and prospective benefits of deformation by methods of drawing with shear (SD) and high pressure torsion (HPT) in a temperature range of dynamic strain aging (DSA) effect, which allow receiving a high complex of physical and mechanical properties. Objectives: The study aims to investigate and analyze features of the structure formation with the combined application of severe plastic deformation (SPD) and the DSA effect during deformation by drawing with shear and high pressure torsion, to establish patterns of the gradient structure formation. Methods Applied: 1. Computer simulation in Deform 3D software to investigate the stress-strain state on materials with various types of a crystalline lattice: copper grade M1 (FCC), Steel 10 (BCC) and titanium VT1-0 (HCP) and a further comparison with experimental results. 2. Microhardness measurement 3. Scanning and transmission electron microscopy. Originality: This research resulted in investigation of the combined effect of the DSA effect and SPD on the gradient structure formation and mechanical properties of metals with various crystalline lattices. Findings: the paper presents the results of the study of the structure formation during non-monotonous plastic deformation of the alloys (steel 10, copper and titanium) with various crystalline lattice types by SD, as well as ECAP and HPT of low-carbon steel in the temperature range of the DSA effect. Deformation mechanisms and features of the deformation behavior on a mesoscopic scale under various deformation treatment modes are analyzed. The temperature range of the DSA effect in steel 10 under ECAP and the fact of the gradient structure formation under HPT are established. Practical Relevance: The study helped to obtain data that can be used to choose the optimal deformation treatment mode with the DSA effect.

scholarly journals Self-Similar Mode of Metals Fragmentation under Severe Plastic Deformation

2019 ◽  
Vol 64 (6) ◽  
pp. 487
Author(s):  
A. V. Khomenko
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Structure ◽  
Structural Defects ◽  
Boundary Density ◽  
Similar Mode ◽  
Self Similar ◽  
Metallic Specimen ◽  
Comparison Of The Results ◽  
Kinetics Of

In the framework of nonequilibrium evolution thermodynamics, the influence of additive fluctuations on the kinetics of structural defects under severe plastic deformation has been studied. The applied method is a new one for the description of fragmentation modes and corresponding self-organization processes. It is found that a fragmented metallic specimen demonstrates a self-similar behavior, which results in the formation of a grain structure with various grain sizes. Such a behavior takes place provided that the probability distribution for the grain boundary density has a power-law dependence. A comparison of the results obtained in the Itˆo and Stratonovich forms demonstrates the absence of qualitative changes in the behavior of the system.

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