Grain-structure refinement in titanium alloy under different loading schedules

Radial-shear rolling (RSR) of titanium alloy billets was realized in a three-high rolling mill. Experimental rolling was simulated using DEFORM software. The purpose was to reveal how stress-strain state parameters, grain structure and hardness vary along the billet’s radius in the stationary stage of the RSR process. It was also the goal to establish a relation between stress state parameters, hardness and grain structure. Changes in the accumulated strain and the stress triaxiality were established by computer simulation. Hardness and grain size changes were obtained after experimental rolling. The novelty aspect is that both computer simulation and experimental rolling showed that there is a ring-shape area with lowered strength in the billet’s cross-section. The radius of the ring-shape area was predicted as a result of the research.

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Characterizing the Effect of Laser Power Density on Microstructure, Microhardness, and Surface Finish of Laser Deposited Titanium Alloy

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4025737 ◽

2013 ◽

Vol 135 (6) ◽

Cited By ~ 26

Author(s):

Rasheedat M. Mahamood ◽

Esther T. Akinlabi ◽

Mukul Shukla ◽

Sisa Pityana

Keyword(s):

Surface Roughness ◽

Titanium Alloy ◽

Power Density ◽

Surface Finish ◽

Laser Power ◽

Optical Microscope ◽

Laser Power Density ◽

Grain Structure ◽

Selection Of

This paper reports the effect of laser power density on the evolving properties of laser metal deposited titanium alloy. A total of sixteen experiments were performed, and the microstructure, microhardness and surface roughness of the samples were studied using the optical microscope (OP), microhardness indenter and stylus surface analyzer, respectively. The microstructure changed from finer martensitic alpha grain to coarser Widmastätten alpha grain structure as the laser power density was increased. The results show that the higher the laser power density employed, the smoother the obtained surface. The microhardness initially increased as the laser power density was increased and then decreased as the power density was further increased. The result obtained in this study is important for the selection of proper laser power density for the desired microstructure, microhardness and surface finish of part made from Ti6Al4V.

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Grain structure and hardness of titanium alloy VT20 after electron-beam welding

Metal Science and Heat Treatment ◽

10.1007/s11041-008-9032-5 ◽

2008 ◽

Vol 50 (3-4) ◽

pp. 187-190 ◽

Cited By ~ 1

Author(s):

V. I. Murav’ev ◽

V. A. Kim ◽

A. A. Shpileva

Keyword(s):

Titanium Alloy ◽

Electron Beam ◽

Electron Beam Welding ◽

Grain Structure ◽

Alloy Vt20

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MODELING OF TWO-PHASE GRAIN STRUCTURE IN THE TITANIUM ALLOY TI-6AL-4V USING CELLULAR AUTOMATA

International Journal for Multiscale Computational Engineering ◽

10.1615/intjmultcompeng.2014007094 ◽

2014 ◽

Vol 12 (1) ◽

pp. 23-31 ◽

Cited By ~ 2

Author(s):

Alfred Krumphals ◽

Cecilia Poletti ◽

Fernando Warchomicka ◽

Martin Stockinger ◽

Christof Sommitsch

Keyword(s):

Titanium Alloy ◽

Cellular Automata ◽

Grain Structure ◽

Two Phase

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Evolution of surface grain structure and mechanical properties in orthogonal cutting of titanium alloy

Journal of Materials Research ◽

10.1557/jmr.2016.444 ◽

2016 ◽

Vol 31 (24) ◽

pp. 3919-3929 ◽

Cited By ~ 8

Author(s):

Jinxuan Bai ◽

Qingshun Bai ◽

Zhen Tong ◽

Chao Hu ◽

Xin He

Keyword(s):

Mechanical Properties ◽

Titanium Alloy ◽

Orthogonal Cutting ◽

Grain Structure ◽

Image Position

Abstract

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The Effects of Laser and Mechanical Forming on the Hardness and Microstructural Layout of Commercially Pure Grade 2 Titanium Alloy Plates

Volume 2: Additive Manufacturing; Materials ◽

10.1115/msec2017-2603 ◽

2017 ◽

Cited By ~ 3

Author(s):

Kadephi V. Mjali ◽

Annelize Els-Botes ◽

Peter M. Mashinini

Keyword(s):

Mechanical Properties ◽

Titanium Alloy ◽

Scanning Speed ◽

Grain Structure ◽

Laser Forming ◽

Major Influence ◽

Forming Process ◽

Commercially Pure ◽

Profound Influence ◽

Pure Grade

This paper illustrates the effects of the laser and mechanical forming on the hardness and microstructural distribution in commercially pure grade 2 Titanium alloy plates. The two processes were used to bend commercially pure grade 2 Titanium alloy plates to a similar radius also investigate if the laser forming process could replace the mechanical forming process in the future. The results from both processes are discussed in relation to the mechanical properties of the material. Observations from hardness testing indicate that the laser forming process results in increased hardness in all the samples evaluated, and on the other hand, the mechanical forming process did not influence hardness on the samples evaluated. There was no change in microstructure as a result of the mechanical forming process while the laser forming process had a major influence on the overall microstructure in samples evaluated. The size of the grains became larger with increases in thermal gradient and heat flux, causing changes to the overall mechanical properties of the material. The thermal heat generated has a profound influence on the grain structure and the hardness of Titanium. It is evident that the higher the thermal energy the higher is the hardness, but this only applies up to a power of 2.5kW. Afterwards, there is a reduction in hardness and an increase in grain size. The cooling rate of the plates has been proved to play a significant role in the resulting microstructure of Titanium alloys. The scanning speed plays a role in maintaining the surface temperatures of laser formed Titanium plates resulting in changes to both hardness and the microstructure. An increase in heat results in grain growth affecting the hardness of Titanium.

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Grain Structure Refinement in Nickel Alloy Welds by Magnetic Arc Stirring

ASME 2011 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2011-57681 ◽

2011 ◽

Cited By ~ 1

Author(s):

Steven L. McCracken ◽

X. Yu ◽

Y. C. Lim ◽

D. F. Farson ◽

S. S. Babu

Keyword(s):

Nickel Alloy ◽

Weld Pool ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Structure Refinement ◽

Grain Structure ◽

High Chromium ◽

Dilution Effects ◽

Alloy Weld

Nickel alloys with high chromium content provide optimum resistant to stress corrosion cracking for service in the reactor coolant system of commercial nuclear power plants. High chromium nickel-base alloys however present many challenges, such as less than ideal weldability and susceptibility to solidification cracking or solid-state cracking depending on welding conditions and dilution effects with dissimilar metals. Moreover, the presence of large solidification grains, typical of nickel alloy weld metals, makes ultrasonic examination of the weldment difficult. Magnetic stirring of the nickel alloy weld pool has the potential to address these challenges and improve joining, overlay welding, cladding, and repair of critical components in commercial nuclear power plants. This study evaluates use of magnetic arc stirring to modify weld pool solidification conditions in order to promote a fine solidification grain structure in nickel alloy welds.

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Study of the Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy grain structure uniformity after bending and annealing

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/177/1/012106 ◽

2017 ◽

Vol 177 ◽

pp. 012106 ◽

Cited By ~ 5

Author(s):

A V Balaykin ◽

E A Nosova ◽

N V Galkina

Keyword(s):

Titanium Alloy ◽

Grain Structure

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Multiscale Modeling of SPD Processes for Grain Refinement

Materials Science Forum ◽

10.4028/www.scientific.net/msf.584-586.1069 ◽

2008 ◽

Vol 584-586 ◽

pp. 1069-1076

Author(s):

Igor V. Alexandrov

Keyword(s):

Multiscale Modeling ◽

Structure Refinement ◽

Grain Morphology ◽

Grain Structure ◽

Boundary Misorientation ◽

Active Deformation ◽

Structure Sensitive ◽

Successful Prediction ◽

Grain Boundary Misorientation ◽

Complex Influence

The results of a recent multiscale computer modeling are presented in this report. The conducted investigations are devoted to the processes, which take place in different metallic materials subjected to severe plastic deformation (SPD). It is presented that the developed models and approaches can be useful in the successful prediction and comprehensive analysis of the peculiarities of material flow and the ways of its homogenization, the understanding of principles of grain structure refinement, the achievement of given grain morphology, grain boundary misorientation spectrum and crystallographic texture, as well as in the evaluation of the active deformation mechanisms, estimating the level of structure-sensitive properties, etc. It is shown that multiscale modeling is a very promising approach which could supply the researchers with the possibility to take into account the complex influence of the different parameters, related to SPD processing and material in order to refine the grain size and obtain homogeneous bulk nanostructured materials.

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