scholarly journals Effect of Multidirectional Forging on the Grain Structure and Mechanical Properties of the Al–Mg–Mn Alloy

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2166 ◽  
Author(s):  
Mikhail Kishchik ◽  
Anastasia Mikhaylovskaya ◽  
Anton Kotov ◽  
Ahmed Mosleh ◽  
Waheed AbuShanab ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Thermomechanical Treatment ◽  
Strain Range ◽  
Grain Structure ◽  
Near Surface ◽  
Fine Grained ◽  
Multidirectional Forging ◽  
Cumulative Strain ◽  
Mean Grain Size

The effect of isothermal multidirectional forging (IMF) on the microstructure evolution of a conventional Al–Mg-based alloy was studied in the strain range of 1.5 to 6.0, and in the temperature range of 200 to 500 °C. A mean grain size in the near-surface layer decreased with increasing cumulative strain after IMF at 400 °C and 500 °C; the grain structure was inhomogeneous, and consisted of coarse and fine recrystallized grains. There was no evidence of recrystallization when the micro-shear bands were observed after IMF at 200 and 300 °C. Thermomechanical treatment, including IMF followed by 50% cold rolling and annealing at 450 °C for 30 min, produced a homogeneous equiaxed grain structure with a mean grain size of 5 µm. As a result, the fine-grained sheets exhibited a yield strength and an elongation to failure 30% higher than that of the sheets processed with simple thermomechanical treatment. The IMF technique can be successfully used to produce fine-grained materials with improved mechanical properties.

scholarly journals The Effect of Isothermal Multi-Directional Forging on the Grain Structure, Superplasticity, and Mechanical Properties of the Conventional Al–Mg-Based Alloy

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Anastasia V. Mikhaylovskaya ◽  
Anton D. Kotov ◽  
Mikhail S. Kishchik ◽  
Alexey S. Prosviryakov ◽  
Vladimir K. Portnoy
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Shear Bands ◽  
Grain Structure ◽  
Structure Evolution ◽  
Multidirectional Forging ◽  
Fine Grain ◽  
Cumulative Strain ◽  
Mean Size ◽  
Bimodal Grain Size

The current study observed a grain structure evolution in the central part and periphery of the sample of an Al–Mg–Mn-based alloy during isothermal multidirectional forging (IMF) at 350 °C with a cumulative strain of 2.1–6.3 and a strain per pass of 0.7. A bimodal grain size distribution with areas of fine and coarse grains was observed after IMF and subsequent annealing. The grain structure, mechanical properties, and superplastic behavior of the samples subjected to IMF with a cumulative strain of 6.3 and the samples exposed to IMF with subsequent cold rolling were compared to the samples exposed to a simple thermo-mechanical treatment. The micro-shear bands were formed inside original grains after the first three passes. The fraction of recrystallized grains increased and the mean size decreased with an increasing cumulative strain from 2.1 to 6.3. Significant improvements of mechanical properties and superplasticity were observed due to the formation of a homogenous fine grain structure 4.8 µm in size after treatment including IMF and subsequent cold rolling.

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.

scholarly journals Influence of Steel Grain Size on Residual Stress in Grinding Processing

2010 ◽  
Vol 638-642 ◽  
pp. 2389-2394 ◽  
Author(s):  
Masahide Gotoh ◽  
Katsuhiro Seki ◽  
M. Shozu ◽  
Hajime Hirose ◽  
Toshihiko Sasaki
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Stress State ◽  
Mechanical Grinding ◽  
Fine Grained ◽  
Residual Stress State ◽  
Analysis Methods ◽  
Average Grain Size ◽  
Fine Grained Steels

The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processed by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension.

scholarly journals Fabrication of (SiC-AlN)/ZrB2 Composite with Nano-Micron Hybrid Microstructure via PCS-Derived Ceramics Route

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Aidong Xia ◽  
Jie Yin ◽  
Xiao Chen ◽  
Zhengren Huang ◽  
Xuejian Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Secondary Phase ◽  
Pressing Temperature ◽  
Xrd Pattern ◽  
Mean Grain Size ◽  
The Mean

In this work, a (SiC-AlN)/ZrB2 composite with outstanding mechanical properties was prepared by using polymer-derived ceramics (PDCs) and hot-pressing technique. Flexural strength reached up to 460 ± 41 MPa, while AlN and ZrB2 contents were 10 wt%, and 15 wt%, respectively, under a hot-pressing temperature of 2000 °C. XRD pattern-evidenced SiC generated by pyrolysis of polycarbosilane (PCS) was mainly composed by 2H-SiC and 4H-SiC, both belonging to α-SiC. Micron-level ZrB2 secondary phase was observed inside the (SiC-AlN)/ZrB2 composite, while the mean grain size (MGS) of SiC-AlN matrix was approximately 97 nm. This unique nano-micron hybrid microstructure enhanced the mechanical properties. The present investigation provided a feasible tactic for strengthening ceramics from PDCs raw materials.

scholarly journals Fabrication of nanoceramic hin-wall tubes by magnetic pulsed compaction and thermal sintering

2005 ◽  
Vol 37 (1) ◽  
pp. 55-60 ◽  
Author(s):  
V.V. Ivanov ◽  
S.Y. Ivin ◽  
V.R. Khrustov ◽  
Y.A. Kotov ◽  
A.M. Murzakaev ◽  
...  
Keyword(s):  
Grain Size ◽  
Wall Thickness ◽  
Thin Wall ◽  
Fine Grained ◽  
Mean Grain Size ◽  
Electrolytic Properties ◽  
Thermal Sintering

Gasproof thin-wall tubes of fine-grained ceramics based on zirconia and gadolinia have been produced by magnetic pulsed compaction and thermal sintering. Data on their structures and electric characteristics are presented. The tubes with a diameter of ~ 15 mm, wall thickness of ~ 0.7 mm, and length up to 80 mm are characterized by an uniform porous-free structure with a mean grain size in the range of 100 - 300 nm. The obtained ceramics possess high electrolytic properties.

Microstructure and Mechanical Performance of AZ31-1.7 Wt.% Si Alloy Processed by Cyclic Channel Die Compression

2010 ◽  
Vol 667-669 ◽  
pp. 457-461
Author(s):  
Wei Guo ◽  
Qu Dong Wang ◽  
Man Ping Liu ◽  
Tao Peng ◽  
Xin Tao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Mechanical Performance ◽  
Chinese Script ◽  
Cast State ◽  
Microstructure And Mechanical Properties ◽  
Mean Grain Size ◽  
The Matrix ◽  
The Mean

Cyclic channel die compression (CCDC) of AZ31-1.7 wt.% Si alloy was performed up to 5 passes at 623 K in order to investigate the microstructure and mechanical properties of compressed alloys. The results show that multi-pass CCDC is very effective to refine the matrix grain and Mg2Si phases. After the alloy is processed for 5 passes, the mean grain size decreases from 300 μm of as-cast to 8 μm. Both dendritic and Chinese script type Mg2Si phases break into small polygonal pieces and distribute uniformly in the matrix. The tensile strength increases prominently from 118 MPa to 216 MPa, whereas the hardness of alloy deformed 5 passes only increase by 8.4% compared with as-cast state.

Effect of Thermomechanical Processing on Grain Size, Texture and Mechanical Properties of Pure Magnesium

2020 ◽  
Vol 985 ◽  
pp. 97-108
Author(s):  
Mouhamadou Moustapha Sarr ◽  
Motohiro Yuasa ◽  
Hiroyuki Miyamoto
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Stress ◽  
Thermomechanical Processing ◽  
Pure Magnesium ◽  
Grain Structure ◽  
Misorientation Distribution ◽  
Processed Material ◽  
Texture Characterization

This study aims to investigate the effect of processing routes (A and Bc) and temperature on microstructure, texture and mechanical properties of pure magnesium was studied in this research. An extruded pure magnesium (~99,9 %) was subjected to severe plastic deformation (SPD) by ECAP. Deformation was conducted at 523K and 473K and two different processing routes (A and Bc) were used to control the texture. The microstructure and texture characterization of the pressed materials were carried out. It was found that the microstructure displayed a bimodal grain structure after two passes and then became homogeneous after four passes following both routes A and Bc. The misorientation distribution was examined and the results revealed that the fraction of high angle grain boundaries (HAGB) was higher at temperature 473K. The texture was randomized following route Bc whereas it became strengthened in route A after four passes. According to the Hall-Petch (HP) relationship, the yield stress of polycrystalline metals increases with a decrease in grain size. In this study, a positive slope k was achieved in the strengthened texture while a negative one was obtained in the softened texture. The ductility of ECAP processed material was considerably improved (from 23% to 38%) without sacrificing the yield stress by route Bc at 423K.

Simulation of Fabrication for Single-Phase Al2O3 Ceramic Tool Materials at Different Fabrication Temperature

2010 ◽  
Vol 150-151 ◽  
pp. 1358-1363
Author(s):  
Bin Fang ◽  
Chuan Zhen Huang ◽  
Chong Hai Xu ◽  
Sheng Sun
Keyword(s):  
Mechanical Properties ◽  
Computer Simulation ◽  
Grain Size ◽  
Monte Carlo ◽  
Single Phase ◽  
Two Dimensional ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Mean Grain Size ◽  
The Mean

The fabrication is a key process for the preparation of ceramic tool materials, which governs the mechanical properties of ceramic tool materials under the condition of the same compositions. A computer simulation coupled with fabrication temperature for the hot-pressing process of single-phase ceramic tool materials has been developed using a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication temperature increases with an increase in fabrication temperature, which is consistent with the experiment results.

Grain Refinement and Texture Evolution in AZ31 Alloy during ECAP Process and Their Effects on Mechanical Properties

2005 ◽  
Vol 475-479 ◽  
pp. 549-554 ◽  
Author(s):  
H.S. Kim ◽  
Hyo Tae Jeong ◽  
Ha Guk Jeong ◽  
Woo Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Texture Evolution ◽  
Az31 Alloy ◽  
Mg Alloys ◽  
Fine Grained ◽  
Ecap Process ◽  
Texture Modification ◽  
Similar Texture

The softening of fine-grained ECAPed AZ31 Mg alloys could be ascribed to the texture modification during ECAP. Lower ECAP temperature is more effective in refining the microstructure. The strength of the ECAPed AZ 31 Mg alloys increased with decrease in grain size when they have similar texture.

Mechanical Properties of Porous Nanophase Materials Measured by Instrumental Indentation

1995 ◽  
Vol 400 ◽  
Author(s):  
H. Van Swygenhoven ◽  
W. Wagner ◽  
J. Löffler
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Annealing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Condensation ◽  
Mean Grain Size ◽  
Nanophase Materials ◽  
The Mean ◽  
Instrumental Indentation

AbstractMechanical properties of nanostructured intermetallic Ni3Al synthesized by the inert-gas condensation technique are studied by means of instrumental indentation using the ICT-CSEMEX indenter. This instrument is a microindenter which continously measures load and displacement. Load-displacement curves are performed as function of grain size, consolidation- and annealing temperature. The mean grain size of the samples are studied by means of x-ray diffraction and small-angle neutron scattering.

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