Grain Refinement of GH4169G Alloy by the Combination of Heat Treatment and Cold Deformation

2014 ◽  
Vol 788 ◽  
pp. 543-548 ◽  
Author(s):  
Lin Jie Huang ◽  
Feng Qi ◽  
Wen Ru Sun ◽  
Pei Tao Hua ◽  
Fang Liu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Refinement ◽  
Cold Deformation ◽  
Phase Precipitation ◽  
Fine Grained ◽  
Optimum Parameters ◽  
Solution Treated ◽  
Average Grain Size ◽  
Δ Phase ◽  
Cold Rolled

The precipitating behavior of δ phase in GH4169G alloy at 910°C was investigated and a novel process for achieving fine-grained GH4169G sheet with average grain size of ASTM13 was proposed. Globular δ phase precipitation precedes that of the plate-like δ phase, forming at grain boundary first and later in grain. After globular δ phase reaches a peak volume, it begins to transform into plate-like in grain boundary, and then the plate-like δ phase forms in grain in certain direction. The grain-fined process includes the following steps:(1) solution treated at a proper temperature, then air cooled; (2) soaked for δ phase precipitation; (3) cold rolled; (4) annealed for recrystallization. Microstructure analysis from optical microscopy (OM) and scanning electron microscopy (SEM) revealed that both plate-like and globular δ phase remarkably restrained the grain growth during annealing recrystallization. The optimum parameters for the grain refinement were determined finally.

scholarly journals Shape Memory Properties and Microstructure of New Iron-Based FeNiCoAlTiNb Shape Memory Alloys

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1253
Author(s):  
Li-Wei Tseng ◽  
Chih-Hsuan Chen ◽  
Wei-Cheng Chen ◽  
Yu Cheng ◽  
Nian-Hu Lu
Keyword(s):  
Grain Boundary ◽  
Shape Memory ◽  
Volume Fraction ◽  
Bending Test ◽  
Recoverable Strain ◽  
Three Point Bending ◽  
Solution Treated ◽  
Average Grain Size ◽  
Shape Memory Properties ◽  
Cold Rolled

The shape memory properties and microstructure of Fe41Ni28Co17Al11.5(Ti+Nb)2.5 (at.%) cold-rolled alloys were studied at the first time using the values reported in constant stress thermal cycling experiments in a three-point bending test. Thermo-magnetization curves of 97% cold-rolled and solution-treated sample aged at 600 °C for 24, 48 and 72 h showed evidence of the martensitic transformation, and the transformation temperatures increased their values from 24 to 72 h. The alloy cold-rolled to 97% and then solution-treated at 1277 °C for 1 h showed that most grains were aligned near <100> in the rolling direction in the recrystallization texture. The intensity of texture was 13.54, and an average grain size was around 400 μm. The sample aged at 600 °C for 48 h showed fully recoverable strain up to 1.6% at 200 MPa stress level in the three-point bending test. However, the experimental recoverable strain values were lower than the theoretical values, possibly due to the small volume fraction of low angle grain boundary, the formation of brittle grain boundary precipitates, and a grain boundary constraint lower than the expected intensity of texture in the samples.

Grain Refinement in AZ91E Magnesium Alloy by Thermo-Mechanical Treatments

2005 ◽  
Vol 475-479 ◽  
pp. 493-496 ◽  
Author(s):  
Atsushi Yamamoto ◽  
Masahiko Ikeda ◽  
Harushige Tsubakino
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
Grain Refinement ◽  
Mechanical Treatment ◽  
Fine Grained ◽  
Heat Treated ◽  
Cold Rolled ◽  
Thermo Mechanical Treatment ◽  
Hot Rolled

In order to improve poor formability in magnesium alloy, grain refinement has been attempted on AZ91E alloy by a thermo-mechanical treatment. Specimens were firstly cold-rolled at 10 %, then solution heat treated at 673 K for 86.4 ks, and hot-rolled at 573 K with about 5 % for four passes, or hot-rolled at 20 % with one pass. The rolled specimens were finally heat treated at 473 to 673 K for 3.6 to 36 ks. Microstructures in the starting material characterized by grain boundary precipitates and aluminum rich regions with about 180 µm in grain size were changed into fine grained microstructures with about 10 to 30 µm in diameter, in which precipitates of Mg17Al12 were uniformly distributed. Although the specimen was prepared by rolling, the (0001) texture was not so remarkable.

scholarly journals Investigation on the Microstructure of ECAP-Processed Iron-Aluminium Alloys

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 219
Author(s):  
Bernd-Arno Behrens ◽  
Kai Brunotte ◽  
Tom Petersen ◽  
Roman Relge
Keyword(s):  
Grain Refinement ◽  
Aluminium Alloys ◽  
Aluminium Content ◽  
Microstructure Development ◽  
Chamber Furnace ◽  
Fine Grained ◽  
Angular Pressing ◽  
Ecap Process ◽  
Average Grain Size ◽  
Forming Temperature

The present work deals with adjusting a fine-grained microstructure in iron-rich iron-aluminium alloys using the ECAP-process (Equal Channel Angular Pressing). Due to the limited formability of Fe-Al alloys with increased aluminium content, high forming temperatures and low forming speeds are required. Therefore, tool temperatures above 1100 °C are permanently needed to prevent cooling of the work pieces, which makes the design of the ECAP-process challenging. For the investigation, the Fe-Al work pieces were heated to the respective hot forming temperature in a chamber furnace and then formed in the ECAP tool at a constant punch speed of 5 mm/s. Besides the chemical composition (Fe9Al, Fe28Al and Fe38Al (at.%—Al)), the influences of a subsequent heat treatment and the holding time on the microstructure development were investigated. For this purpose, the average grain size of the microstructure was measured using the AGI (Average Grain Intercept) method and correlated with the aforementioned parameters. The results show that no significant grain refinement could be achieved with the parameters used, which is largely due to the high forming temperature significantly promoting grain growth. The holding times in the examined area do not have any influence on the grain refinement.

Electrical properties of ultrafine-grained yttria-stabilized zirconia ceramics

1997 ◽  
Vol 12 (9) ◽  
pp. 2374-2380 ◽  
Author(s):  
Shusheng Jiang ◽  
Walter A. Schulze ◽  
Vasantha R. W. Amarakoon ◽  
Gregory C. Stangle
Keyword(s):  
Grain Size ◽  
Oxygen Vacancy ◽  
Grain Boundary ◽  
Oxygen Vacancies ◽  
Synthesis Process ◽  
Physical Parameters ◽  
Fine Grained ◽  
Oxygen Ion ◽  
Average Grain Size ◽  
Vacancy Concentrations

Nanoparticles of yttria-doped tetragonal zirconia polycrystalline ceramics (Y-TZP) with an average crystallite size of less than 9 nm were prepared by a combustion synthesis process. Dense and fine-grained (<200 nm) Y-TZP ceramics were obtained by fast-firing using temperatures lower than 1400 °C and dwell times of less than 2 min. Impedance spectroscopy was employed to measure conductivities of oxygen vacancies in the grain and the grain boundary of the fine-grained Y-TZP. The relationships between the concentration of the oxygen vacancies in the grain boundary and measurable physical parameters were determined semiquantitatively. The oxygen vacancy concentrations and activation energies for the oxygen-ion conduction in the grain and the grain boundary of the fine-grained Y-TZP were found to be independent of the average grain size in the average grain-size range of 90–200 nm. These experimental results suggest that, in order to retain the abnormally high oxygen vacancy concentrations of the Y-TZP nanoparticles and thus enhance the oxygen-ion conductivity, it may be necessary to decrease the average grain size to approximately 10 nm.

scholarly journals Study of Structure and Mechanical Properties of Fine-Grained Aluminum Alloys Al-0.6wt.%Mg-Zr-Sc with Ratio Zr:Sc = 1.5 Obtained by Cold Drawing

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 316 ◽  
Author(s):  
Aleksey Nokhrin ◽  
Iana Shadrina ◽  
Vladimir Chuvil’deev ◽  
Vladimir Kopylov
Keyword(s):  
Thermal Stability ◽  
Cold Deformation ◽  
Annealing Treatment ◽  
Cold Drawing ◽  
Fine Grained ◽  
Prolonged Annealing ◽  
Intermetallic Particles ◽  
Average Grain Size ◽  
Fine Grained Structure ◽  
Thermal Stability Of

The thermal stability of a fine-grained (FG) aluminum wire has been studied in Al-0.6Mg-Zr-Sc alloys with various scandium and zirconium contents. Specimens were obtained by induction casting followed by cold deformation. The FG alloys have been demonstrated to have high thermal stability of the structure and properties due to the annealing pretreatment (320 °C, 2 h, before drawing), which results in deposition of Al3(ScxZr1−x) intermetallic particles. It has been determined that following a prolonged annealing treatment (400 °C, 100 h), the alloys retain a uniform fine-grained structure with an average grain size of 2.4–2.8 μm whereas their microhardness measures 405–440 MPa.

Grain Refinement by Combined ECAE/Extrusion and Dieless Drawing Processes for AZ31 Magnesium Alloy Tubes

2010 ◽  
Vol 654-656 ◽  
pp. 735-738 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Tetsuhide Shimizu ◽  
Kenichi Manabe
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Process ◽  
Az31 Magnesium Alloy ◽  
Drawing Process ◽  
Fine Grained ◽  
Tube Extrusion ◽  
Dieless Drawing ◽  
Average Grain Size

Grain refinement processing by severe deformation, combined equal-channel angular extrusion (ECAE) processing and conventional tube extrusion, is applied to AZ31 magnesium alloy. By a combination of ECAE processing and tube extrusion, a fabricated tube, with outer and inner diameters of 2 mm and 1 mm, respectively, has fine, homogeneous, and equiaxed grain structure with an average grain size of 1.5m. Tensile test results indicate that the fine-grained tubes exhibited a superplasticity potential m value of 0.55.The maximum elongation (688%) is obtained at a temperature of 673K. Furthermore, the tubes fabricated by combined ECAE/extrusion process is applied to dieless drawing process without using any tool and die.As a result, dieless drawing limit is enhanced due to high m value achieved by combined ECAE/Extrusion process. From these results, the effectiveness of new grain refinement processing for fabricating fine-grained tubes and its application for dieless drawing process to fabricate the fine tubes was demonstrated experimentally.

Investigation on Mechanical Properties and Formability of Cross Roll Rolled Ni-10Cr Alloy

2012 ◽  
Vol 724 ◽  
pp. 476-480
Author(s):  
Kuk Hyun Song ◽  
Han Sol Kim ◽  
Won Yong Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Boundary ◽  
Cold Rolling ◽  
Grain Refinement ◽  
Initial Material ◽  
Rolled Material ◽  
Average Grain Size ◽  
Back Scattering ◽  
Boundary Characteristic

This study evaluated the microstructure and mechanical properties enhancement of cross roll rolled Ni-10Cr alloy, comparing with conventional rolled material. Cold rolling was carried out to 90% thickness reduction and subsequently annealed at 700 °C for 30 min to obtain the fully recrystallized microstructure. For annealed materials after rolling, to investigate the grain boundary characteristic distributions, electron back-scattering diffraction technique was introduced. Application of cross roll rolling on Ni-10Cr alloy contributed to the notable grain refinement, consequently, average grain size was refined from 135 μm in initial material to 4.2 μm in cross roll rolled material. These refined grain size led to an enhanced mechanical properties such as yield and tensile strengths. Furthermore, <111>//ND texture in CRR material was well developed than that of CR material, which contributed to the mechanical properties and formability enhancement.

EFFECT OF Al ON MICROSTRUCTURE AND PROPERTIES OF In718 ALLOY

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1066-1073
Author(s):  
FANG LIU ◽  
SHULIN YANG ◽  
WENRU SUN ◽  
SHOUREN GUO ◽  
ZHUANGQI HU
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Tensile Ductility ◽  
Sharp Decrease ◽  
Compact Form ◽  
Phase Precipitation ◽  
Σ Phase ◽  
Δ Phase

Compared with the conventional In 718 alloy, the addition of Al at the level of 1.24% and 1.50% greatly increases the precipitation of γ′ phase and the compact form of γ″/γ′/γ″ structure, which has been demonstrated in previous studies. The δ phase precipitation at the grain boundaries is noticeably suppressed. Large amount of Laves phase (( Fe , Ni , Cr )2( Nb , Mo )), small amount of M 7 C 3 carbide and σ phase (( Fe , Ni )( Cr , Mo , Nb )) are precipitated at the grain boundaries. After aging at 680°C, the grain boundary precipitates are increased significantly. Large amount needle-like σ phase is precipitated at the grain boundary in the alloy with 1.50% Al . After aging at 680°C for 1000h, the grain boundary precipitates are worsened further, but the coarsening of the compact form γ″/γ′/γ″ is lighter than the γ″ phase in the normal In 718 alloy. The tensile strength at room temperature and 680°C are increased due to Al increasing. While the tensile ductility and impact toughness of the alloy decrease significantly, and a sharp decrease has been found during the long term aging at 680°C. The mechanism by which Al influencing the microstructure and mechanical properties of In 718 alloy is to be discussed.

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