Microstructure Evolution of Copper by Three Roll Planetary Milling

2018 ◽  
Vol 279 ◽  
pp. 44-48 ◽  
Author(s):  
Yu Wei Zhou ◽  
Ze Ning Mao ◽  
Ying Liu ◽  
Jing Tao Wang
Keyword(s):  
Dynamic Recrystallization ◽  
Pure Copper ◽  
Milling Process ◽  
Planetary Mill ◽  
Grain Structure ◽  
Coarse Grain ◽  
Engineering Strain ◽  
Fine Grain ◽  
Equiaxed Grains ◽  
Equiaxed Grain

The microstructure of commercial pure copper TP2 tube by three roll planetary mill processing was investigated. Due to work hardening and subsequent softing by dynamic recrystallization during milling process,the coarse grain structure of the copper transformed to fine grain structure. The grain refinement is achieved along the axial moving in general; in the reducing zone, the sample has a gradient structure along the radial direction; uniform equiaxed grain with size of ~2 μm could be obtained at the outlet. The initiation of dynamic recrystallization occurred in the three roll planetary mill the reduction engineering strain reach ~30%, where some equiaxed grains replaced the elongated grains because of recrystallization.

Fabrication of very-high-strength pure copper with fine grain structure through multi-axial diagonal forging

2020 ◽  
Vol 269 ◽  
pp. 127663
Author(s):  
Jae Kun Lee ◽  
Sang-Chul Kwon ◽  
Hyo-Tae Jeong ◽  
Sang-Ho Han ◽  
Sung Hyuk Park
Keyword(s):  
Pure Copper ◽  
High Strength ◽  
Grain Structure ◽  
Fine Grain ◽  
Very High

scholarly journals INVESTIGATIONS OF DENSITY AND POROSITY OF COATINGS MADE OF CERAMIC-POLYMERIC OR COMPOSITES WITH QUASI-CRYSTALS OBTAINED WITH GAS-DETONATION METHOD AND METHOD OF GAS-DYNAMIC SPUTTERING

2020 ◽  
Vol 2020 (7) ◽  
pp. 4-11
Author(s):  
Ol'ga Sil'chenko ◽  
Marina Siluyanova ◽  
Petr Hopin
Keyword(s):  
Grain Structure ◽  
Titanium Carbonitride ◽  
Coarse Grain ◽  
Friction Unit ◽  
Gradual Change ◽  
Gas Detonation ◽  
Fine Grain ◽  
Gas Dynamic ◽  
Quasi Crystals ◽  
Maximum Parameters

The work purpose consists in the development of the procedure for density and strength definition through the method of hydro-static weighing in relation to titanium carbonitride-based coatings. The development object – quasi-crystals based titanium carbonitride clad with nickel. Novelty and urgency of this work are based on the creation of polymeric antifriction materials intended for operation in the mode of hydro-dynamic friction. Frictionless and slider bearings with anti-friction coatings are the most efficient structures allowing the considerable increase of capacity and reliability of friction unit operation in machinery. There are presented microstructure photos of coatings obtained with the method of gas-dynamic sputtering. As a result of the technology developed it is defined that at the base a coating has the VN20 coarse-grain which has maximum parameters of static strength (bending, tearing and adhesion strength) at the expense of its structure and coarse grain. As we move forward from the layer adjoining the base to the operation one of the coating we observe the decrease of structure grain (from 100 to 15 mkm) and a gradual change of the composition, micro-hardness increase. As a result a carrying layer of KNTP35 coating has maximum parameters of long strength at the expense of a fine-grain structure and composition. It is characterized with increased resistance to thermal blow, tacking, spalling and higher impact elasticity and wear-resistance. In the paper there is offered a method of hydro-static weighing for the determination of density and porosity regarding coatings. According to the optimum technological mode are made samples and their porosity and density are investigated.

The Challenges Associated with the Formation of Equiaxed Grains during Additive Manufacturing of Titanium Alloys

2018 ◽  
Vol 770 ◽  
pp. 155-164 ◽  
Author(s):  
David H. St John ◽  
Stuart D. McDonald ◽  
Michael J. Bermingham ◽  
Sri Mereddy ◽  
Arvind Prasad ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Temperature Gradients ◽  
Metal Alloys ◽  
Grain Structure ◽  
Grain Structures ◽  
Columnar Grains ◽  
High Cooling Rates ◽  
Columnar Grain ◽  
Equiaxed Grains ◽  
Equiaxed Grain

It is well established that columnar grain structures usually form when metal alloys are used to additively manufacture components. A challenging goal is to produce an equiaxed grain structure throughout the component to remove anisotropy and refine the grain size in order to improve its mechanical performance. The high cooling rates and associated high temperature gradients are the main reasons for the formation of columnar grains via epitaxial growth of each added layer of material. There appear to be limited strategies for promoting equiaxed nucleation of grains. In addition to cooling rate and temperature gradient, we explore other variables such as the potency of natural or added inoculant particles and the composition of the alloy, and their possible impact on the nucleation of equiaxed grains. Although changing the composition can help, finding a suitably potent nucleant particle is a major challenge. Operating parameters can also influence the microstructure and optimization to produce equiaxed grains may be possible. The limitations of these strategies and possible ways to overcome them are evaluated.

Isotropic and Anisotropic Nanocrystalline NdFeB-Based Magnets Prepared by Spark Plasma Sintering and Hot Deformation

2012 ◽  
Vol 510-511 ◽  
pp. 307-314 ◽  
Author(s):  
Zhong Wu Liu ◽  
Y.L. Huang ◽  
H.Y. Huang ◽  
X.C. Zhong ◽  
Hong Ya Yu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Hot Deformation ◽  
Grain Structure ◽  
Coarse Grain ◽  
Fine Grain ◽  
Plasma Sintering ◽  
Melt Spun ◽  
Spark Plasma

Isotropic and anisotropic NdFeB permanent magnets were prepared by Spark Plasma Sintering (SPS) and SPS followed hot deformation (HD), respectively, using melt spun NdFeB ribbons with various compositions as starting materials. It is found that, based on RE-rich composition, SPSed magnets sintered at low temperatures (<700 C) almost maintained the uniform fine grain structure inherited from rapid quenching. At higher temperatures, a distinct two-zone (coarse grain and fine grain zones) structure was formed in the SPSed magnets. The SPS temperature and pressure have important effects on the grain structure, which led to the variations in the magnetic properties. By employing low SPS temperature and high pressure, high-density magnets with negligible coarse grain zone and an excellent combination of magnetic properties can be obtained. For single phase NdFeB alloy, because of the deficiency of Nd-rich phases, it is relatively difficult to consolidate micro-sized melt spun powders into high density bulk magnet, but generally a larger particle size is beneficial to achieve better magnetic properties. Anisotropic magnets with a maximum energy product of ~38 MGOe were produced by the SPS+HD process. HD did not lead to obvious grain growth and the two-zone structure still existed in the hot deformed magnets. The results indicated that nanocrystalline NdFeB magnets without significant grain growth and with excellent properties could be obtained by SPS and HD processes.

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

CONTINUOUS-CAST 45-12 DUCTILE IRON

Alloy Digest ◽  
1989 ◽  
Vol 38 (4) ◽  
Keyword(s):  
Continuous Casting ◽  
Ductile Iron ◽  
Heat Treating ◽  
Grain Structure ◽  
Continuous Cast ◽  
Good Surface ◽  
Fine Grain ◽  
High Speeds ◽  
Good Surface Finish ◽  
Iron Grade

Abstract Ductile Iron grade 45-12 produced by continuous casting has consistent density and fine grain structure. It is the softest of the regular grades of ductile iron and it machines at high speeds with good surface finish. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties. It also includes information on heat treating, machining, and joining. Filing Code: CI-58. Producer or source: Federal Bronze Products Inc..

KETOS

Alloy Digest ◽  
1960 ◽  
Vol 9 (8) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Tool Steel ◽  
Heat Treating ◽  
Grain Structure ◽  
Steel Company ◽  
Fine Grain ◽  
Crucible Steel

Abstract KETOS is an oil-hardening non-deforming tool steel having deep hardening qualities with a fine grain structure. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as deformation. It also includes information on forming, heat treating, and machining. Filing Code: TS-96. Producer or source: Crucible Steel Company of America.

scholarly journals Microstructural Evolutions of 2N Grade Pure Al and 4N Grade High-Purity Al during Friction Stir Welding

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3606
Author(s):  
Tomoya Nagira ◽  
Xiaochao Liu ◽  
Kohasaku Ushioda ◽  
Hidetoshi Fujii
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
High Purity ◽  
Cube Texture ◽  
Grain Structure ◽  
Welding Temperature ◽  
Friction Stir ◽  
Continuous Dynamic Recrystallization ◽  
Dislocation Annihilation

The grain refinement mechanisms along the material flow path in pure and high-purity Al were examined, using the marker insert and tool stop action methods, during the rapid cooling friction stir welding using liquid CO2. In pure Al subjected to a low welding temperature of 0.56Tm (Tm: melting point), the resultant microstructure consisted of a mixture of equiaxed and elongated grains, including the subgrains. Discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and geometric dynamic recrystallization are the potential mechanisms of grain refinement. Increasing the welding temperature and Al purity encouraged dynamic recovery, including dislocation annihilation and rearrangement into subgrains, leading to the acceleration of CDRX and inhibition of DDRX. Both C- and B/-type shear textures were developed in microstructures consisting of equiaxed and elongated grains. In addition, DDRX via high-angle boundary bulging resulted in the development of the 45° rotated cube texture. The B/ shear texture was strengthened for the fine microstructure, where equiaxed recrystallized grains were fully developed through CDRX. In these cases, the texture is closely related to grain structure development.

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