scholarly journals Конструкционные прочностные параметры и разрушение ультрамелкозернистого титана Grade 4, полученного методом равноканального углового прессования РКУП-К

2019 ◽  
Vol 89 (4) ◽  
pp. 541
Author(s):  
И.В. Смирнов
Keyword(s):  
Plastic Deformation ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Experimental Studies ◽  
Tensile Tests ◽  
Grain Structure ◽  
Angular Pressing ◽  
Pure Grade ◽  
Localized Plastic Deformation ◽  
Titanium Structure

AbstractProcessing of metals and alloys by severe plastic deformation (SPD) is accompanied by refinement of the material grain structure, which can increase their physicomechanical properties, for instance, unique tensile strength. However, studies of mechanical properties of materials after SPD are usually limited by tensile tests and other properties of strength and fracture are not sufficiently considered. This article presents experimental studies of ultimate tensile strength, impact toughness, fracture toughness, as well as respective surfaces of fracture of initial and ultrafine-grained pure Grade 4 titanium fabricated by continuous equal channel angular pressing. The results demonstrated that upon high ultimate tensile strength after SPD the material demonstrates decreased resistance against initiation and propagation of cracks upon single loading. The fracture surface of both states of titanium structure reveals mainly localized plastic deformation.

Fatigue of Ultra-Fine Grained α-Brass

2014 ◽  
Vol 891-892 ◽  
pp. 1125-1130
Author(s):  
Yoshikazu Nakai ◽  
Takuto Imanaka ◽  
Daiki Shiozawa
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Severe Plastic Deformation ◽  
Fatigue Limit ◽  
High Strength ◽  
Angular Pressing ◽  
Fine Grain ◽  
Proof Strength

Combined methods to obtain ultra-fine grain (UFG) α-brass samples are proposed. Severe plastic deformation followed by recrystallization was conducted, where multiple rolling and equal channel angular pressing (ECAP) were employed. Recrystallization was accomplished by heat-treatment after the severe plastic deformation, and the grain size after the severe plastic deformation was decreased. By multiple rolling, plates with thickness of 0.1 mm and grain size of 1.0 μm were obtained. By ECAP process, square bar with cross-section of 6 mm × 6 mm and minimum grain size of 4.1 μm was obtained. The 0.2 % proof strength, ultimate tensile strength, and fatigue limit were increased with the value of inverse square root of grain size (Hall-Petch relationship). Then, the 0.2 % proof strength of UFG brass was tenfold, the ultimate tensile strength and the fatigue limit were two fold increases from the conventional α-brass. Because of the high strength, the scatter of fatigue strength of UFG brass was large, which reflects the sensitivity to defects in material.

scholarly journals Influence of Hydrostatic Extrusion on the Mechanical Properties of the Model Al-Mg Alloys

2021 ◽  
Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Hydrostatic Extrusion ◽  
Microstructure Formation ◽  
Initial State ◽  
Degree Of Deformation ◽  
Al Mg Alloys

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.

scholarly journals Microstructural Characterization of Laser Weld of Hot-Stamped Al-Si Coated 22MnB5 and Modification of Weld Properties by Hybrid Welding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3943
Author(s):  
Hana Šebestová ◽  
Petr Horník ◽  
Šárka Mikmeková ◽  
Libor Mrňa ◽  
Pavel Doležal ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fusion Zone ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Laser Weld ◽  
Martensitic Microstructure ◽  
Laser Welds ◽  
Weld Properties ◽  
Weld Fusion Zone

The presence of Al-Si coating on 22MnB5 leads to the formation of large ferritic bands in the dominantly martensitic microstructure of butt laser welds. Rapid cooling of laser weld metal is responsible for insufficient diffusion of coating elements into the steel and incomplete homogenization of weld fusion zone. The Al-rich regions promote the formation of ferritic solid solution. Soft ferritic bands cause weld joint weakening. Laser welds reached only 64% of base metal's ultimate tensile strength, and they always fractured in the fusion zone during the tensile tests. We implemented hybrid laser-TIG welding technology to reduce weld cooling rate by the addition of heat of the arc. The effect of arc current on weld microstructure and mechanical properties was investigated. Thanks to the slower cooling, the large ferritic bands were eliminated. The hybrid welds reached greater ultimate tensile strength compared to laser welds. The location of the fracture moved from the fusion zone to a tempered heat-affected zone characterized by a drop in microhardness. The minimum of microhardness was independent of heat input in this region.

Strength of Commercial Aluminum Alloys after Equal Channel Angular Pressing and Post-ECAP Processing

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Ecap Processing ◽  
Angular Pressing

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.

Fracture Behavior of an AlMgMnSc Alloy at Different Temperatures

2021 ◽  
Vol 1016 ◽  
pp. 292-296
Author(s):  
Yuliya Igorevna Borisova ◽  
Diana Yuzbekova ◽  
Anna Mogucheva
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Fine Grained ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Elongation To Failure

An Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (wt. %) alloy was studied in the fine-grained state obtaining after equal channel angular pressing. The mechanical behavior of alloy at the temperatures 173 K, 298 K and 348 K and at strain rate 1×10–3 s–1 is studied. Increase of the temperature testing from 173 K to 348 K decreases the yield stress by 80 MPa, the ultimate tensile strength by 60 MPa while elongation-to failure increases by a factor of 1.4. It was found that at temperatures of 298 and 173 K, the studied alloy mainly demonstrates the mode of ductile fracture, and at a temperature of 348 K the mechanism can be described as mixed ductile-brittle fracture. It was also established that of the studied alloy is the temperature dependence of the size of the dimples on the fracture surface. The formation of smaller dimples in the samples deformed at 298 K was observed.

Tensile Tests for Cast Stainless Steel: Evolution of the RCC-M Code

2018 ◽  
Author(s):  
Arnaud Blouin ◽  
Mathieu Couvrat ◽  
Félix Latourte ◽  
Julian Soulacroix
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Ultimate Tensile Strength ◽  
Tensile Tests ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Different Diameters ◽  
Cast Stainless Steel ◽  
Acceptance Tests ◽  
Do So

In the framework of a pressurized water reactor primary loop replacement, elbows of different types were produced in cast austenitic stainless steel grade Z3CN 20-09 M. For that type of component, acceptance tests to check the sufficient mechanical properties include room and hot temperature tensile tests, following the RCC-M CMS – 1040 and EN 10002 specifications. A large test campaign on standard 10mm diameter specimens was performed and exhibited a high scattering in yield stress and ultimate tensile strength values. As a consequence, some acceptance tensile tests failed to meet the required minimal values, especially the ultimate tensile strength. Optical and electronic microscopy revealed that the low values were due to the presence of very large grain compared to the specimen gage diameter. However, tensile tests strongly rely on the hypothesis that the specimen gage part can be considered as a representative volume element containing a number of grains large enough so that their variation in size and orientation gives a homogeneous response. To confirm the origin of the scattering, a huge experimental tensile test campaign with specimens of different diameters was conducted. In parallel, FE calculations were also performed. From all those results, it was concluded that it was necessary to improve the RCC-M code for that type of test for cast stainless steel: to do so, a modification sheet was sent and is being investigated by AFCEN.

scholarly journals Influence of Hydrogen Content on the Microstructure and Mechanical Properties of ER5183 Wires

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Yilong Han ◽  
Songbai Xue ◽  
Renli Fu ◽  
Lihao Lin ◽  
Zhongqiang Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Hydrogen Content ◽  
Tensile Tests ◽  
Plastic Strain Rate ◽  
Drawing Process ◽  
Welding Wire ◽  
Unstable Crack ◽  
Microstructure And Mechanical Properties

This work focused on the influence of hydrogen content on the microstructure and mechanical properties of ER5183 Al-Mg-Mn alloy wires for aluminum alloy welding. The hydrogen content of the ER5183 wires was measured, the macroscopic and microscopic morphologies of fractures were observed as well as the microstructure of the wires, and the tensile strength of the wires was also tested and investigated. The experimental results demonstrated three typical irregular macroscopic fractures of the wires appeared during the drawing process when the hydrogen content exceeded 0.23 μg/g. In the meantime, the aggregated pores were observed in the microstructure of the ϕ5.2 mm wire with the hydrogen content of 0.38 μg/g. Such defects may become the origin of cracks in subsequent processing and tensile tests. Moreover, higher hydrogen content in the ϕ5.2 mm welding wire will bring obvious changes in the fracture surface, which are internal cracks and micropores replacing the original uniform and compact dimples. With the higher hydrogen content, the tensile strength and plastic strain rate of ϕ1.2 mm wires would decrease. At the same time, unstable crack propagation would occur during the process of plastic deformation, leading to fracture. Considering the mechanical properties and microstructure, the hydrogen content of the ER5183 wires should be controlled below 0.23 μg/g.

Grain Refinement of Magnesium Alloys by CONFORM: A Continuous Severe Plastic Deformation Route?

2012 ◽  
Vol 706-709 ◽  
pp. 1781-1786 ◽  
Author(s):  
You Liang He ◽  
Fei Gao ◽  
Bao Yun Song ◽  
Rong Fu ◽  
Gui Ming Wu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Large Scale ◽  
Tensile Tests ◽  
Mg Alloys ◽  
Uniaxial Tensile ◽  
Batch Mode ◽  
Angular Pressing ◽  
Conform Process

Effective grain refinement through equal channel angular pressing (ECAP) for magnesium (Mg) alloys has been demonstrated by many researchers. Although with the capability to achieve superplasticity, the batch mode nature of this method and the required repetitive processing to attain ultrafine grained structure have prohibited it from being widely used in large-scale industrial production. In this study, a well-established metal forming method – the continuous extrusion forming (CONFORM) process – was employed as a severe plastic deformation route to refine the microstructure of Mg alloys. Cast Mg-3%Al-1%Zn (AZ31) rods were used as the feedstock and the cast structure (grain size of ~150 microns) was refined to ~1 micron afteronepass CONFORM extrusion. Uniaxial tensile tests of the as-extruded samples were conducted at a temperature of 473K and an elongation of ~200% was achieved under a strain rate of 1×10-4s-1. The significant grain refinement effect was attributed to the severe shear deformation occurred during the CONFORM process, which is very similar to ECAP but with even higher effective strains. The most important advantage of CONFORM over ECAP is that the former is a continuous route, so it is able to produce long products. It was also shown that CONFORM could be an additional forming method for Mg alloys to conventional rolling, forging and extrusion.

Mechanical Properties and Fracture Study of Alumina Dispersion Hardened Copper-Based Nano-Composite at Elevated Temperatures

2013 ◽  
Vol 829 ◽  
pp. 583-588 ◽  
Author(s):  
Ali Dalirbod ◽  
Yahya A. Sorkhe ◽  
Hossein Aghajani
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fracture Surface ◽  
Yield Strength ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Optical Microscope ◽  
Tensile Fracture ◽  
Different Temperatures

Alumina dispersion hardened copper-base composite was fabricated by internal oxidation method. The high temperature tensile fracture of Cu-Al2O3 composite was studied and tensile strengths were determined at different temperatures of 600, 680 and 780 °C. Microstructure was investigated by means of optical microscope and field emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS). Results show that, ultimate tensile strength and yield strength of copper alumina nanocomposite decrease slowly with increasing temperature. The yield strength reaches 119 MPa and ultimate tensile strength reaches 132 MPa at 780 °C. Surface fractography shows a dimple-type fracture on the fracture surface of the tensile tests where dimple size increases with increasing testing temperature and in some regions brittle fracture characteristics could be observed in the fracture surface.

Effects of Electromagnetic Stirring Plus Single Pulse on the Microstructures and Properties of High Strength Al-Cu Alloy Welds

2011 ◽  
Vol 391-392 ◽  
pp. 1225-1229
Author(s):  
Cheng Gang Yang ◽  
Ge Ping Liu ◽  
Yu Hua Chen ◽  
Wei Ping Xu
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Weld Joint ◽  
High Strength ◽  
Single Pulse ◽  
Elongation Rate ◽  
Electromagnetic Stirring ◽  
Grain Structure ◽  
Cu Alloy ◽  
Columnar Grains

The effect of single pulse, electromagnetic stirring plus single pulse on the microstructures and properties of high strength Al-Cu alloy welds is investigated. The results show that the grain structure of weld under conventional MIG welding are coarse, oriented columnar grains, the ultimate tensile strength of weld joint is 286.5 MPa, the elongation rate of joint is 2.4%. The thermal gradient at the solid-liquid interface in the welding pool is decreased and the density of heterogeneous nucleation is enhanced by electromagnetical stirring plus single pulse, which resulted in the coarse and oriented columnar grains transforming to fine equiaxed grains; morphology and distribution of α(Al)-CuAl2 eutectic along the grain boundaries are improved, so it significantly improves the mechanical property of weld joint, the ultimate tensile strength of weld joint is up to 326.0 MPa, the elongation rate of joint reaches 7.8%.

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