scholarly journals Grain Structure Evolution and Mechanical Properties of Multi-Channel Spiral Twist Extruded AA5083

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1276
Author(s):  
Dina M. Fouad ◽  
Waleed H. El-Garaihy ◽  
Mohamed M. Z. Ahmed ◽  
Ibrahim Albaijan ◽  
Mohamed M. El-Sayed Seleman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Grain Refinement ◽  
Electron Backscatter Diffraction ◽  
Comprehensive Evaluation ◽  
Structural Evolution ◽  
Grain Structure ◽  
Structure Evolution

This study presents a comprehensive evaluation of the effects of multi-channel spiral twist extrusion (MCSTE) processing on the mechanical properties and structural evolution of AA5083. The structural evolution and texture developed were mapped by electron backscatter diffraction (EBSD) for three successive passes and compared with an as-annealed plate. An evaluation of the hardness and tensile properties was presented and correlated with the EBSD findings. The displayed EBSD results revealed that grain refinement was strongly associated with the presence of a high density of low-angle grain boundaries (LAGBs) after one pass, which developed into fine grains of less than 20 μm and high-angle grain boundaries (HAGBs) after three MCSTE passes. The three pass processing led to a 65% reduction in grain size. This reduction in grain size was coupled with an enhancement in the hardness and tensile properties. Additionally, the crystallographic texture study represented a slightly random texture due to the presence of intermetallic particles in AA5083. This study demonstrates the efficacy of MCSTE as a grain refinement tool.

Effect of La-Rich Misch Metal on Microstructure and Mechanical Properties of As-Extruded Mg-14Li-3Al Alloy

2011 ◽  
Vol 391-392 ◽  
pp. 32-36 ◽  
Author(s):  
Bin Liu ◽  
Jing Huai Zhang ◽  
Zhong Yi Niu ◽  
Jun Qing Li
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Properties ◽  
Grain Refinement ◽  
Hot Extrusion ◽  
Vacuum Melting ◽  
Melting Method ◽  
Misch Metal ◽  
Microstructure And Mechanical Properties

The as-cast Mg-14Li-3Al-(0-0.9)RE alloys were prepared with vacuum melting method, then processed by hot extrusion. The microstructure and tensile properties were investigated. The results show that both addition of RE and extrusion deformation can refine the grain size. Al3La compounds are formed with addition of La-rich misch metal. The as-extruded Mg-14Li-3Al-0.6RE alloy obtains the finest grain size (4.28 μm) and the highest mechanical properties (σb=222.75 MPa, δ=23.8%), which is related to the grain refinement and the formation of Al3La.

Microstructure Evolution during High Pressure Torsion of AZ80 Magnesium Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 300-305 ◽  
Author(s):  
Dogan Arpacay ◽  
Sang Bong Yi ◽  
Miloš Janeček ◽  
Adem Bakkaloglu ◽  
Lothar Wagner
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Pressure ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Significant Variation ◽  
High Pressure Torsion ◽  
Grain Structure ◽  
Az80 Magnesium Alloy

The microstructure evolution during high pressure torsion and its influence on the mechanical properties of AZ80 magnesium alloy is presented in this study. Significant grain refinement was observed after high pressure torsion, while the homogeneity of the grain structure increases with the number of revolutions. Grain size decreases to about 50 nm after 15 revolutions. The microhardness profiles measured at through-thickness and through-width directions show no significant variation at different positions of the sample. Moreover, the negligible effect of the revolution number on the microhardness value was observed.

scholarly journals Effect of Deformation on Precipitation and the Microstructure Evolution during Multistep Thermomechanical Processing of Al-Zn-Mg-Cu Alloy

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1409
Author(s):  
Jinrong Zuo ◽  
Longgang Hou ◽  
Xuedao Shu ◽  
Wenfei Peng ◽  
Anmin Yin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Electron Microscope ◽  
Grain Boundaries ◽  
Grain Refinement ◽  
Hot Rolling ◽  
Hot Deformation ◽  
Rolling Process ◽  
Intermediate Annealing ◽  
Short Period

In order to obtain fine grained structure efficiently, a new multi-step rolling process (MSR: pre-deformation + intermediate annealing + hot deformation) was applied in Al-Zn-Mg-Cu plates. Conventional hot rolling (CHR) was also carried out as a contrast experiment. The evolution of microstructures and improvement of mechanical properties were analyzed by optical microscope, scanning electron microscope, transmission electron microscope, X-ray diffractometer, and tensile tests. The results show that the MSR process can obtain finer longitudinal grain size and better mechanical properties than CHR, which can be explained as follows: spheroidization of precipitates wrapped by high density dislocations could be promoted by increased pre-deformation; numerous ordered substructures were formed during short-period intermediate annealing at high temperature; in the subsequent hot rolling process, the retained spherical precipitates pinned dislocations and boundaries. With the increase of accumulated strain, low angle grain boundaries gradually transformed into high angle grain boundaries, leading to grain refinement. With the increased pre-deformation (MSR1 20 + 60%, MSR2 40 + 40%, MSR3 60 + 20%), the effect of grain refinement and plasticity improvement gradually weakened. The optimum thermomechanical process (MSR1 solid solution + pre-deformation (300 °C/20%) + intermediate annealing (430 °C/5 min) + hot deformation (400 °C/60%)) was obtained, which can increase elongation by ~25% compared with the CHR process, while maintaining similar high strength for reduced longitudinal grain size.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

MICROCAST-X MAR-M-247

Alloy Digest ◽  
1995 ◽  
Vol 44 (5) ◽  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Properties ◽  
Negative Impact ◽  
Rupture Properties

Abstract The Microcast-X process produces a substantially finer grain size that improves mechanical properties in MAR-M-247 with modest negative impact on rupture properties above 1600 F (871 C). This datasheet provides information on composition, microstructureand tensile properties as well as creep and fatigue. It also includes information on casting. Filing Code: Ni-481. Producer or source: Howmet Corporation.

Effect of Composite Master Alloy on Mechanical Properties and Electrochemical Corrosion of ZL101 Alloy

2013 ◽  
Vol 749 ◽  
pp. 407-413
Author(s):  
Hong Xu ◽  
Xin Zhang ◽  
Ji Ping Ren ◽  
Min Peng ◽  
Shi Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Grain Refinement ◽  
Master Alloy ◽  
Mass Fraction ◽  
Electrochemical Corrosion ◽  
Corrosion Performance ◽  
Obvious Effect ◽  
Mechanical Properties And Corrosion

The mechanical properties and corrosion performances of the ZL101 alloy modified by the composite master alloy were investigated. The results showed that the master alloy had not only obvious effect of grain refinement, but also a significant role in refining dendrite grain of ZL101 alloy. The grain size decreased dramatically from 150μm to 62μm when the addition of composite master alloy is up to 0.5%(mass fraction) and the temperature is 720 for 30 minutes,. Its tensile strength and elongation increased by 27% and 42% respectively. The grain refinement of ZL101 alloy decreased its corrosion performance. The morphology of Si changed into globular from needle modified by NaF, instead of AlTiB.

Physical Based Microstructure Modelling Coupled with Nucleation Theory during and after Hot Forming of AA5083

2010 ◽  
Vol 89-91 ◽  
pp. 509-514
Author(s):  
Pavel Sherstnev ◽  
Christof Sommitsch ◽  
Stefan Mitsche ◽  
Carsten Melzer
Keyword(s):  
Aluminium Alloy ◽  
Hot Rolling ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Grain Structure ◽  
Nucleation Theory ◽  
Structure Evolution ◽  
Nucleation Sites ◽  
Nucleation Mechanisms ◽  
Backscatter Diffraction

A physical model based on three types of dislocations and three nucleation sites for recrystallized grain is applied to hot rolling simulation. This model was implemented into a commercial Finite Element (FE) analysis package FORGE 2008 to calculate both the structure evolution during and the recrystallized volume fraction after hot working of aluminium alloy 5083. It is shown that the main nucleation mechanisms in the aluminium alloy are the particle stimulated nucleation (PSN) and nucleation at grain boundaries. Hence the precipitation kinetics during homogenisation was investigated by use of the thermodynamic calculation software MatCalc. To validate the simulation results hot rolling experiments were performed by means of a laboratory mill. The grain structure evolution was analysed by electron backscatter diffraction (EBSD).

scholarly journals Novel grain refinement of AZ91E magnesium alloy and the effect on hot tearing during solidfication

2021 ◽  
Author(s):  
Abdallah Elsayed
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Hot Tearing ◽  
Grain Refining ◽  
Grain Refiner ◽  
Structural Applications ◽  
Hot Tearing Susceptibility

For the A1-5Ti-1B grain refiner, the addition of 0.1 wt.% provided a 68 % reduction in grain size as compared to the unrefined AZ91E alloy at a holding time of five minutes. Grain growth restriction by TiB₂ particles was the source of grain refinement. With the addition of A1-5Ti-1B, only a small reduction in hot tearing susceptibility ws observed because large TiA1₃ particles bonded poorly with the eutectic and blocked feeding channels.The addition of 1.0 wt.% A1-1Ti-3B provided a grain size reduction of 63% as compared to the unrefined AZ91E alloy at a holding time of five minutes. The grain refinement with A1-1Ti-3B addition was attributed to a combination of TiB₂ grain growth restriction and A1B₂ nucleating sites. A significant reduction in hot tearing susceptibility was observed with A1-1Ti-3B addition as a result of a higher cooling rate and shorter local soldification time as compared to the AZ91E alloy. The reduction in hot tearing susceptibility was attributed to the good interface between eutectic and TiB₂ particles. Both grain refiners demonstrated a good resistance to fading during the holding times investigated. In addition, the AZ91E + A1-5Ti-1B and AZ91E + A1-1Ti-3B castings showed much fewer dislocation networks as compared to the untreated AZ91E casting.The development of efficient A1-Ti-B refiners can also improve castability of magnesium alloys. In addition, the fade resistant A1-Ti-B grain refiners can reduce operating costs and maintain productivity on the foundry floor. Thus, magnesium alloy with A1-Ti-B treatment have the potential for more demanding structural applications in the automobile and aerospace industries. Vehicle weight in the aerospace and automotive industries directly impacts carbon emissions and fuel efficiency. An increase in the use of lightweight materials for structural applications will result in lighter vehicles. Low density materials, such as magnesium (1.74 g/cm³) are a potential alternative to aluminium (2.70 g/cm³), to reduce component weight in structural applications.However, current magnesium alloys still do not have adequate mechanical properties and castability to meet the performance specifications of the automotive and aerospace industries. Grain refinement can significantly improve mechanical properties and reduce hot tearing during permanent mould casting. Recently, Al-Ti-B based grain refiners have shown potential in grain refining magnesium-aluminum alloys such as AZ91E. This study investigates the grain refining efficiency and fading of A1-5Ti-1B and A1-1Ti-3B in AZ91E magnesium alloy and their subsequent effect on hot tearing.The grain refiners were added at 0.1, 0.2, 0.5 and 1.0 wt.% levels. For the grain refinement and fading experiments, the castings were prepared using graphite moulds with holding times of 5, 10 and 20 minutes. For the hot tearing experiments, castings were produced representing the optimal addition level of each grain refiner. The castings were prepared using a permanent mould with pouring and mould temperatures of 720 and 180 ºC, respectively. The castings were characterized using SEM, TEM, optical microscopy and thermal analysis.

The Effect of Oxygen, Nitrogen, and Hydrogen on the Mechanical Properties of Cb-752

1974 ◽  
Vol 96 (3) ◽  
pp. 201-206 ◽  
Author(s):  
M. W. Mahoney ◽  
N. E. Paton
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Uniform Distribution ◽  
Base Alloy ◽  
Uniaxial Tensile ◽  
Hardness Testing ◽  
Strength Parameters ◽  
Brittle Transition ◽  
Effect Of Oxygen

Uniaxial tensile properties of the niobium-base alloy Cb-752 have been determined as a function of oxygen, nitrogen, and hydrogen content over a temperature range of −196 C to 200 deg C. Each of these impurities increased the temperature at which a ductile-brittle transition occurs. Although ductility was severely reduced, strength parameters were relatively unchanged making detection of embrittlement by hardness testing difficult. Impurity levels for embrittlement were sufficiently low and the affinity of Cb-752 for contamination sufficiently great that processing operations require strict control. The mechanism of this impurity embrittlement is not well understood. However, observations of fracture surfaces of brittle failures reveal mixed intergranular cleavage with a uniform distribution of precipitates throughout grain boundaries. These observations are discussed in the light of current theories.

Effect of the Mg3N2 Sub-Micron Particle on the Grain Refinement of AZ80 Alloy

2022 ◽  
Vol 327 ◽  
pp. 45-53
Author(s):  
Jiehua Li ◽  
Maria Pammer ◽  
Ernst Neunteufl ◽  
Peter Schumacher
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Liquid State ◽  
High Performance ◽  
Great Loss ◽  
Micron Particle ◽  
Deformation Ability ◽  
Semi Solid ◽  
Az80 Alloy

AZ80 alloy has been widely used to produce high performance Mg casting and wrought parts for high-end applications due to its high mechanical properties and deformation ability. However, at least two important issues still need to be solved in order to further improve its mechanical properties and deformation ability. Firstly, the grain size of α-Mg in AZ80 alloy is relatively large (more than 1000 µm) due to a lack of efficient grain refinement methodologies. Secondly, the size of the eutectic Mg17Al12 phase is also large and the distribution of the eutectic Mg17Al12 phase is continuous, which is very harmful for the mechanical properties, in particular to elongation. In this paper, these two important issues are investigated by adding Mg3N2 sub-micron particle into AZ80 alloy and thereby refining the α-Mg and the eutectic Mg17Al12 phase. Firstly, the Mg3N2 sub-micron particle was directly added into AZ80 alloy by using mechanically stirring in the semi-solid state, subsequently the melting temperature was increased above the liquidous temperature, and finally the melting was casted in the liquid state. It was found that the grain size of α-Mg can be refined from 883.8 µm to 169.9 µm. More importantly, the eutectic Mg17Al12 phase was also refined and the distribution became discontinuous. It should be noted that directly adding the Mg3N2 sub-micron particle into AZ80 alloy leads to a great loss of the Mg3N2 sub-micron particle due to the weak wetting behavior between the Mg3N2 sub-micron particle and Mg melt. The second methodology through mixing Mg3N2 sub-micron particles with AZ91 chips using a twin extruder was also used to prepare AZ91 master alloy with 3wt.% Mg3N2 sub-micron particle, which was subsequently added into AZ80 alloy in the liquid state. In this way, a significant grain refinement of α-Mg and a simultaneous refinement of the eutectic Mg17Al12 phase in AZ80 alloy was also achieved. The grain size of α-Mg can be refined from 883.8 µm to 325.9 µm. However, no significant grain refinement by using UST was observed. Instead, the grain size increases from 325.9 µm to 448.6 µm, indicating that the Mg3N2 sub-micron particle may lose its grain refinement potency due to possible aggregation and clustering. This paper provides an efficient and simple methodology for the grain refinement of α-Mg and the simultaneous refinement of the eutectic Mg17Al12 phase in AZ80 alloy.

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