Yield strength increase of a CoCrNi medium entropy alloy by interstitial nitrogen doping at maintained ductility

2020 ◽  
Vol 178 ◽  
pp. 391-397 ◽  
Author(s):  
Igor Moravcik ◽  
Hynek Hadraba ◽  
Linlin Li ◽  
Ivo Dlouhy ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Yield Strength ◽  
Nitrogen Doping ◽  
Strength Increase ◽  
Interstitial Nitrogen

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

Copper Effect on Mechanical Properties of Al-CNF Composite Material Elaborated by Liquid Metallurgy with Induction Melting

2018 ◽  
Vol 941 ◽  
pp. 2018-2023
Author(s):  
Paul Royes ◽  
Nicolas Masquelier ◽  
Thierry Breville ◽  
David Balloy
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Carbon Nanofibers ◽  
Aluminum Matrix ◽  
Casting Process ◽  
Stir Casting ◽  
Aluminum Matrix Composite ◽  
Strength Increase ◽  
Induction Melting ◽  
Coated Carbon

Aluminum-Carbon nanoFibers (CNF) composites produce by stir casting process present a yield strengths (YS) and an ultimate tensile strength (UTS) improved up to 33%. The hardening of the Al-CNF composite was considered as the sum of elementary contributions of effects: natural hardness of pure Al; grain size; dislocation density; elements in solid solution; CNF. In order to quantify CNF effect, calculation was performed to quantify the contribution to yield strength of each other’s mechanisms. This theoretical calculation was compared to experimental results and the real effect of CNF on yield strength increase was estimated between 10 and 16%. Figure SEQ Figure \* ARABIC 1: Graphical Abstract (copper dots on CNF / stir casting process / contributions to hardening) Keywords: Aluminum matrix composite; copper-coated carbon nanofibers; liquid metallurgy elaboration; mechanical properties; hardening effect

Mechanical Properties and Fracture Mechanism of TiCp/ZA-12 Composites

2006 ◽  
Vol 324-325 ◽  
pp. 671-674
Author(s):  
Wang Xiang ◽  
Xiao Hua Xue
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Cleavage Fracture ◽  
Fracture Mechanism ◽  
Experimental Results ◽  
Fracture Model ◽  
Strength Increase ◽  
Dimple Fracture ◽  
Mixed Fracture

TiCp/ZA-12 composites have been fabricated by XDTM method and stirring-casting techniques. The tests for mechanical properties reveal that the tensile strength and strength increase with increasing fraction of TiC particles. When the fraction of TiC particles increase up to 10%, the tensile strength and yield strength are 390MPa and 340MPa, respectively and they increase by 11% and 17% than that of matrix respectively. From the analysis of fractography we can see that mixed fracture of cleavage fracture and dimple fracture exists in the TiCp/ZA-12 composites, and fractured particles are not found. Finally the fracture model of composites has been established based on the experimental results.

Local Mechanical Properties of Highly Porous Si3N4 for Trabecular Bone Replacement

2015 ◽  
Vol 662 ◽  
pp. 142-146
Author(s):  
Zuzana Pramuková Vilčeková ◽  
Monika Kašiarová ◽  
Magdaléna Precnerová Domanická ◽  
Miroslav Hnatko ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Yield Strength ◽  
Trabecular Bone ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Polyurethane Foams ◽  
Strength Increase ◽  
Bone Replacement ◽  
Highly Porous

The study deals with the development of highly porous undegradable ceramics based on silicon nitride as potential replacement of trabecular bone. These materials were produced using replication method with polyurethane foams as pore-forming agents to achieve similar porous structure to trabecular bone. Prepared porous ceramics had a bimodal pore structure with macro-pores larger than 200 μm and micro-pores smaller than 1 μm in diameter, which are necessary for tissue ingrowths, cell adhesion, adsorption of biological metabolites and nutrition delivery in organism. The microstructure and local mechanical properties (Young’s modulus and Yield strength) were evaluated and compared with human trabecular bone. Results showed that studied porous materials have satisfactory porosity and pore sizes for trabecular bone replacement. Young’s modulus of bone was 12.6 ± 2.23 GPa and porous silicon nitride samples ranged from 10.9 ± 3.38 GPa to 12.9 ± 1.13 GPa. The values of Yield strength of trabecular bone was determined as 493 ± 30.7 MPa and the values of porous samples varied from 250 ± 19.3 MPa to 558 ± 36.5 MPa. Young’s modulus and Yield strength increase with increasing of the pre-sintering temperature and multiple infiltrations.

The Classification of Disposable Mechanical Elements

2012 ◽  
Vol 163 ◽  
pp. 86-90
Author(s):  
Yue Feng Li ◽  
Xu Dong Pan ◽  
Guang Lin Wang
Keyword(s):  
Yield Strength ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Properties ◽  
Strength Increase ◽  
Type I ◽  
Type Ii ◽  
Cycle Fatigue ◽  
Mechanical Elements ◽  
Design Stress

Disposable mechanical elements with extremely short lives are widely used in the aerospace and defense fields. To reliably evaluate the life of disposable mechanical elements, many attentions were concentrated in the fatigue properties of disposable mechanical elements. According to the different meanings of static strength for metals, disposable mechanical elements are divided into two groups with different fatigue properties: extremely low cycle fatigue module for Type I with ultimate strength as design stress and low cycle fatigue module for Type II with yield strength as design stress. The Kuroda model and a cumulative damage model consisting of the Miners rule and the sequential law are used in the fatigue design process of the Type I. To the Type II, the Manson-Coffin model is suitable for conventional applications but more attempts are still conducted to further improve stress levels. The Type II with increasing load sequences are specially treated, since the cyclic yield strength of certain materials under pulsating stress closing to the yield strength increase with the deepening of fatigue damage. Consequently, under the increasing pulsating cyclic loading, the later load whose amplitude is higher than the initial yield strength will be permitted.

scholarly journals Microstructural Change during the Interrupted Quenching of the AlZnMg(Cu) Alloy AA7050

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2554 ◽  
Author(s):  
Thomas M. Kremmer ◽  
Phillip Dumitraschkewitz ◽  
Daniel Pöschmann ◽  
Thomas Ebner ◽  
Peter J. Uggowitzer ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Phase Distribution ◽  
Atom Probe ◽  
Industrial Applications ◽  
Treatment Temperature ◽  
Strength Increase ◽  
Artificial Ageing ◽  
Cu Alloy

This study reports on the effect of interrupted quenching on the microstructure and mechanical properties of plates made of the AlZnMg(Cu) alloy AA7050. Rapid cooling from the solution heat treatment temperature is interrupted at temperatures between 100 and 200 °C and continued with a very slow further cooling to room temperature. The final material’s condition is achieved without or with subsequent artificial ageing. The results show that an improvement in the strength–toughness trade-off can be obtained by using this method. Interrupted quenching at 125 °C with peak artificial ageing leads to a yield strength increase of 27 MPa (538 MPa to 565 MPa) compared to the reference material at the same fracture toughness level. A further special case is the complete omission of an artificial ageing treatment with interrupted quenching at 200 °C. This heat treatment exhibits an 20% increase in fracture toughness (35 to 42 MPa m−1/2) while retaining a sufficient yield strength of 512 MPa for industrial applications. A detailed characterization of the relevant microstructural parameters like present phases, phase distribution and precipitate-free zones is performed using transmission electron microscopy and atom probe tomography.

Effect of the Lattice Parameter on Brittle Fracture of Metals at Low Temperatures

2020 ◽  
Vol 989 ◽  
pp. 290-295
Author(s):  
Alexander A. Khlybov ◽  
Yury G. Kabaldin ◽  
Maksim S. Anosov
Keyword(s):  
Brittle Fracture ◽  
Yield Strength ◽  
Low Temperatures ◽  
Mechanical Characteristics ◽  
Relative Elongation ◽  
Lattice Parameter ◽  
Strength Increase ◽  
Metallic Materials

The paper presents the results of tests of metallic materials at low temperatures. It is shown that with the decreasing of temperature, the mechanical characteristics of materials change significantly: strength limits, yield strength increase, and relative elongation decrease. It is shown that the temperature of the brittle-viscous transition depends on the lattice parameter of the materials. The higher the lattice parameter is, the lower is the temperature of the brittle-viscous transition. It is shown that the lattice parameter can be used to estimate the temperature of the brittle-viscous transition

Effect of Nb content on the strength of Cu–Nb filamentary microcomposites

2000 ◽  
Vol 15 (9) ◽  
pp. 1889-1893 ◽  
Author(s):  
Sun Ig Hong
Keyword(s):  
Experimental Data ◽  
Yield Strength ◽  
Yield Stress ◽  
Plastic Flow ◽  
Volume Fraction ◽  
Strength Increase ◽  
Unit Cells ◽  
Nb Content ◽  
Good Agreement

The yield strength of Cu–Nb filamentary microcomposites was predicted as a function of Nb content by modifying the barrier strengthening model. To predict the variation of the yield strength with Nb content, the interfilamentary spacing was calculated as a function of Nb content on the basis of the assumption that Nb filaments are distributed regularly along the sides of triangular unit cells. The yield stress can be described as the sum of the substructural strengthening component and the filament boundary strengthening term. The good agreement between the prediction and the experimental data suggests that the strength increase in Cu–Nb filamentary microcomposites with increasing Nb content results mostly from increasing the volume fraction of Nb filaments, which act as barriers to plastic flow.

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