Synthesis of submicrometer-grained-ultrahigh-carbon steel containing 10% aluminum by ball-milling of powders

1996 ◽  
Vol 11 (11) ◽  
pp. 2725-2730 ◽  
Author(s):  
Eric M. Taleff ◽  
Mamoru Nagao ◽  
Yoshio Ashida ◽  
Oleg D. Sherby
Keyword(s):  
Grain Size ◽  
Ball Milling ◽  
Bulk Material ◽  
Hot Isostatic Pressing ◽  
High Strength ◽  
Tensile Tests ◽  
Grain Sizes ◽  
Ultrahigh Carbon Steel ◽  
Processing Step ◽  
Size Powder

An ultrahigh-carbon (1.25 wt.%) steel alloy containing 10 wt.% aluminum (UHCS–10Al) was processed by a powder metallurgy technique. Gas-atomized powders were subjected to ball-milling in an attritor in order to obtain a submicrometer grain size. Powder material was consolidated by both hot isostatic pressing (HIP) and by hot isopressure extrusion (HIE). Bulk material with submicrometer grain sizes was produced from attrited powders. The chemical composition and microstructure of this material are characterized at each processing step, from atomization through consolidation. Tensile tests show that a high strength results from the submicrometer grain size produced in the bulk material.

scholarly journals Experimental and Numerical Investigations on Microcoining of Stainless Steel 304

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Gap-Yong Kim ◽  
Muammer Koç ◽  
Jun Ni
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Bulk Material ◽  
High Strength ◽  
304 Stainless Steel ◽  
Feature Size ◽  
Stainless Steel 304 ◽  
Metallic Parts ◽  
Type 304 ◽  
Type 304 Stainless Steel

Increasing demands for miniature metallic parts have driven the application of microforming in various industries. Only a limited amount of research is, however, available on the forming of miniature features in high strength materials. This study investigated the forming of microfeatures in Type 304 stainless steel by using the coining process. Experimental work was performed to study the effects of workpiece thickness, preform shape, grain size, and feature size on the formation of features ranging from 320μmto800μm. It was found that certain preform shapes enhance feature formation by allowing a favorable flow of the bulk material. In addition, a flow stress model for Type 304 stainless steel that took into consideration the effects of the grain and feature sizes was developed to accurately model and better understand the coining process. Weakening of the material, as the grain size increased at the miniature scale, was explained by the Hall–Petch relationship and the feature size effect.

Effect of Grain Size on Mechanical Properties of Mg-0.3at.%Y Dilute Alloy

2018 ◽  
Vol 941 ◽  
pp. 790-795
Author(s):  
Rui Xiao Zheng ◽  
Ichiro Kawarada ◽  
Wu Gong ◽  
Akinobu Shibata ◽  
Hidetoshi Somekawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
High Pressure Torsion ◽  
Tensile Elongation ◽  
Tensile Tests ◽  
Subsequent Annealing ◽  
High Yield ◽  
Grain Sizes ◽  
Mean Grain Size

In this study, a Mg-0.3at.%Y alloy was provided for a severe plastic deformation by high pressure torsion (HPT) and subsequent annealing. After the HPT by 5 rotations, nanocrystalline structures with a mean grain size of 0.23 μm having deformed characteristics were obtained. Fully recrystallized microstructures with mean grain sizes ranging from 0.66 μm to 32.7 μm were obtained by subsequent annealing at various temperatures. Room temperature tensile tests revealed that ultrafine grained (UFG; grain sizes smaller than 1 μm) specimen exhibited very high yield strength over 250 MPa but limited ductility. In contrast, good balance of strength and ductility was realized in fine grained specimens with grain sizes around 2~5 μm. Particularly, the yield strength and total tensile elongation of a specimen with a mean grain size of 2.13 μm were 184 MPa and 37.1%, respectively, which were much higher than those of pure Mg having a similar grain size. The significant effects of grain size and Y addition on the mechanical properties were discussed.

scholarly journals Role of Automotive Industry in Global Warming

2019 ◽  
Vol 62 (3) ◽  
pp. 197-201
Author(s):  
Shahid Hussain Abro ◽  
Alidad Chandio ◽  
Iftikhar Ahmed Channa ◽  
Abdulaziz S. Alaboodi
Keyword(s):  
Air Pollution ◽  
Grain Size ◽  
Global Warming ◽  
Automotive Industry ◽  
High Strength ◽  
Chemical Compositions ◽  
Light Weight ◽  
Grain Sizes ◽  
Heat Treated

Global warming and air pollution by human made gases such as CO2, is mainly produced by automotive industry that results in great risk for human health. The aim of this study is to reduce the above problem by using the high strength materials with low density in the manufacturing of automotive vehicles. An approach applied here is to enhance the strength by reducing the grain size, lowering the density and increasing elongation. Four steel samples with different chemical compositions were selected. Samples were heat treated from 850 °C to 1250 °C and cooled in water. Grain size distribution was calculated using matrox inspector software and result was plotted using origin. It was found that 850 °C has lowest and 1250 °C has highest grain sizes. Strength of steel can be increased not only by adding the alloying elements but also by controlling grain size. Light weight material consumes lower fuel and emits lower CO2, thus it minimizes the global warming and air pollution.  

Dislocation study of ARMCO iron processed by ECAP

2016 ◽  
Vol 1818 ◽  
Author(s):  
Jairo Alberto Muñoz ◽  
Oscar Fabián Higuera ◽  
José María Cabrera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Dislocation Density ◽  
Deformation Behavior ◽  
Armco Iron ◽  
Tensile Tests ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Cylindrical Samples

ABSTRACTThe aim of this work was to study the deformation behavior of an Armco iron after severe plastic deformation by equal channel angular pressing (ECAP). Particular attention was paid to predict the dislocation density by different approaches like the model proposed by Bergström. Experimental measures of dislocation density by different techniques are used in the discussion. Cylindrical samples of ARMCO iron (8mm of diameter, 60mm of length) were subjected to ECAP deformation using a die with an intersecting channel of Φ=90° and outer arc of curvature of ψ= 37° die. Samples were deformed for up to 16 ECAP passes following route Bc. The mechanical properties of the material were measured after each pass by tensile tests. The original grain size of the annealed iron (70 μm) was drastically reduced after ECAP reaching grain sizes close to 300nm after 16 passes.

Broad Search of Better Thermoelectric Oxides via First-Principles Computations

2015 ◽  
Vol 1774 ◽  
pp. 25-30
Author(s):  
Qing Hao ◽  
Hongbo Zhao ◽  
Na Lu
Keyword(s):  
Grain Size ◽  
First Principles ◽  
Bulk Material ◽  
Bulk Materials ◽  
Computational Tools ◽  
Novel Materials ◽  
Grain Sizes ◽  
Thermoelectric Oxides ◽  
The Mean ◽  
New Criterion

ABSTRACTThe advancement of computational tools for material property predictions enables broad search of novel materials for various energy-related applications. However, challenges still exist in accurately predicting the mean free paths (MFPs) of electrons and phonons in a high-throughput frame for thermoelectric property predictions, which largely hinders the computation-driven search for novel materials. In this work, this need is eliminated under the small-grain-size limit, in which these MFPs are restricted by the grain sizes within a bulk material. A new criterion for ZT evaluation is proposed for general nanograined bulk materials and is demonstrated with representative oxides.

scholarly journals Effect of Grain Size on the Hydrogen Diffusion Process in Steel Using Cellular Automaton Approach

2012 ◽  
Vol 706-709 ◽  
pp. 1568-1573 ◽  
Author(s):  
N. Yazdipour ◽  
D.P. Dunne ◽  
Elena V. Pereloma
Keyword(s):  
Grain Size ◽  
Cellular Automaton ◽  
Hydrogen Diffusion ◽  
High Strength ◽  
Hydrogen Uptake ◽  
Grain Sizes ◽  
Ca Model ◽  
Simulation Results ◽  
Do So

The role of microstructure in susceptibility to hydrogen uptake and property degradation is being evaluated using a number of high strength pipeline steels. To do so, a cellular automaton (CA) model has been used to examine the effect of grain size, as a first step in assessing the influence of microstructure. The simulation results of hydrogen diffusion into microstructures with different grain sizes are presented.

Superplastic Behavior and Cavitation for WC-Co Cemented Carbides

2005 ◽  
Vol 475-479 ◽  
pp. 2991-2994 ◽  
Author(s):  
Hiroyuki Hosokawa ◽  
Koji Shimojima ◽  
Masaru Kawakami ◽  
Shoken Sano ◽  
Osamu Terada ◽  
...  
Keyword(s):  
Grain Size ◽  
Volume Fraction ◽  
Tensile Tests ◽  
The Other ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Cavity Volume ◽  
Superplastic Behavior ◽  
Grain Sizes

Superplastic behavior and cavitation were investigated for WC-15 mass % Co cemented carbides with the WC grain sizes of 0.7 µm (A) and 5.2 µm (B), WC-10 mass % Co cemented carbide with the WC grain size of 1.5 µm (C) and WC-5 mass % Co cemented carbides with the WC grain sizes of 0.5 µm (D) and 2.5 µm (E) by tensile tests at 1473 K. WC contiguity were 0.51, 0.31, 0.27, 0.56 and 0.49, respectively. The large elongations about 200 % were obtained for the B and the C having smaller values of WC contiguity compared to the other cemented carbides. The values of cavity volume fraction for them were less for the other cemented carbides, furthermore, cavities formed at WC/WC interfaces. Therefore, it is noted that the distribution of the Co phase is important for superplasticity of the cemented carbides.

Failure behavior of alumina and alumina/silicon carbide nanocomposites with natural and artificial flaws

1997 ◽  
Vol 12 (12) ◽  
pp. 3307-3315 ◽  
Author(s):  
F. Meschke ◽  
P. Alves-Riccardo ◽  
G. A. Schneider ◽  
N. Claussen
Keyword(s):  
Silicon Carbide ◽  
Grain Size ◽  
Crack Opening ◽  
Hot Isostatic Pressing ◽  
Slip Casting ◽  
High Strength ◽  
Failure Behavior ◽  
Pure Alumina ◽  
Sic Nanoparticles ◽  
High Crack

Alumina/silicon carbide nanocomposites with 5 vol.% SiC nanoparticles were produced by slip casting, pressureless sintering, and hot isostatic pressing. The grain size dependence of both the bend strength and fracture toughness have been investigated. The strength exceeds 1 GPa at a grain size of 1.7 μm. Crack opening displacements (COD) were measured, revealing that crack tip toughness is considerably lower than in pure alumina and an R-curve behavior is unlikely to occur. By introducing artificial pores with a size of 60 μm, the micromechanical fracture process has been studied in both pure alumina and nanocomposites. In contrast to alumina, where an annular precrack forms prior to fracture, it is suggested that precrack formation is strongly impeded in the nanocomposites and failure is controlled by microcrack initiation. The high strength of Al2O3/SiC nanocomposites seems to be the result of an unusually high crack initiation stress.

scholarly journals Novel Tensile Test Jig and Mechanical Properties of WC-Co Synthesized by SHIP and HIP Process

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 884
Author(s):  
A-Ra Jo ◽  
Ji-Seob An ◽  
Sun-Hyung Kim ◽  
Myeong-Sik Jeong ◽  
Young-Hoon Moon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Tensile Testing ◽  
Hot Isostatic Pressing ◽  
High Strength ◽  
Tensile Tests ◽  
Isostatic Pressing ◽  
Manufacturing Method ◽  
Axial Tensile ◽  
Co Alloys

Tungsten carbide-cobalt (WC-Co) alloys have various mechanical properties according to their Co content and manufacturing method. High-strength materials such as WC-Co alloys are usually manufactured using various sintering methods. In this study, WC-Co was compared according to the Co content and manufacturing method using the sinter-hot isostatic pressing process. Furthermore, an additional test was performed to investigate the effect of post-hot isostatic pressing (HIP) treatment on the mechanical properties. To compare tensile strength, threaded end and shoulder end specimens are generally applied in axial tensile testing with hard metals. However, it is extremely difficult to shape WC-Co by machining. A tensile testing jig for a shoulder end specimen is, therefore, proposed. Tensile tests were conducted using the proposed jig, and microstructure, hardness, and impact tests were carried out to compare the mechanical properties. The microstructure evolution was obtained by decreasing the Co content and applying the HIP treatment, resulting in changes in Young’s modulus and strength. The results indicated that the proposed jig of the axial tensile test could be applied to the extremely hard WC-Co, and the mechanical properties of WC-Co could be modified by the Co content and HIP treatment control.

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