scholarly journals Structure and Mechanical Properties of AlMg4.5 And AlMg4.5Mn Wires Extruded by Kobo Method

2014 ◽  
Vol 59 (2) ◽  
pp. 473-479 ◽  
Author(s):  
M. Jaskowski ◽  
K. Pieła ◽  
L. Błaz
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Flow Instability ◽  
Cold Deformation ◽  
Tensile Tests ◽  
Strength Properties ◽  
Extrusion Ratio ◽  
Groove Rolling ◽  
One Step ◽  
Lüders Bands

Abstract The influence of the number of extrusion steps in KoBo method (at the same total extrusion ratio of λ = 100) on structure, mechanical properties and work hardening characteristics of AlMg4.5 and AlMg4.5Mn (AA5083) alloys was investigated. It was found that one-step extrusion leads to the formation of recrystallised structure of the material, while the use of two-step extrusion yields a fibrous structure of a “mixed” type, i.e. containing areas where the intensive recovery effects are associated with partially recrystallised structure. As a consequence, the strength properties of the latter extrudate are much higher in both as extruded state and after the subsequent cold rolling. In all cases, the tensile stress-strain curves of the extrudates show the flow stress serrations that are typical for the Portevin - LeChatelier (P-L) effect. In a few tensile tests, the P-L effect was preceded by the plastic flow instability being typical for the occurrence of Lüders bands. Both AlMg4.5 and AlMg4.5Mn extruded wires show a monotonic increase of the work hardening that results from the following cold deformation in the groove rolling.

Effect of Plastic Deformation on the Mechanical Properties and Microstructure of Homogenized AZ80 Magnesium Alloy

2010 ◽  
Vol 139-141 ◽  
pp. 180-184
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Li Hui Lang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Grain Boundaries ◽  
Gradual Increase ◽  
Tensile Tests ◽  
Extrusion Ratio ◽  
Extrusion Temperature ◽  
Second Phase ◽  
Strength And Plasticity ◽  
Az80 Alloy

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75) and extrusion temperatures (300°C, 330°C, 360°C, 390°C, 420°C) on the mechanical properties and microstructure of homogenized AZ80 alloy have been investigated through the tensile tests and via metallographic microscope observation. The results show that the alloy’s grain is small and small amounts of black hard and brittle second-phase β (Mg17Al12) are precipitated uniformly along the grain boundary causing the gradual increase of the alloy’s tensile strength at 330°C. When the extrusion temperature is up to 390°C, the grain size increases significantly, but the second phase precipitation along grain boundaries transforms into continuous and uniform-distribution precipitation within the grain. In this case, when the extrusion ratio is 60, the alloy’s tensile strength reaches its peak 390Mpa. As the extrusion temperature increases, inhomogeneous precipitation of the second-phase along grain boundaries increases, causing the decrease of the alloy’s strength. At the same temperature, the tensile strength increases firstly and then decreases as extrusion ratio increases. With the gradual increase of the refinement grain, the dispersed precipitates increase and the alloy’s tensile strength and plasticity reach their peaks when the extrusion temperature is 390°C. As the grain grows, the second phase becomes inhomogeneous distribution, and the alloy’s strength and plasticity gradually decrease.

Improving the Mechanical Properties of AZ31 Mg Alloy by High Ratio Extrusion

2006 ◽  
Vol 503-504 ◽  
pp. 865-870 ◽  
Author(s):  
Yongjun Chen ◽  
Qu Dong Wang ◽  
Jianguo Peng ◽  
Chun Quan Zhai
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
High Ratio ◽  
Extrusion Ratio ◽  
Mg Alloy ◽  
Fine Grained ◽  
Az31 Mg Alloy ◽  
Industry Applications ◽  
One Step ◽  
The One

Experiments were conducted both to evaluate the potential for grain refinement, the subsequent mechanical properties at room temperature in samples of AZ31 Mg alloy and also to investigate the relationship between one-step and two-step high ratio extrusion (HRE). The one-step HRE was undertaken using a high extrusion ratio of 70:1 at 250, 300 and 350°C. And the two-step HRE was conducted with an extrusion ratio of 7 for the first step at 250, 300 and 350°C, followed by a second-step extrusion with an extrusion ratio of 10 at 250, 300 and 350°C. The initial grain size in the AZ31 ingot was 100μm and that after one-step HRE became similar to 5μm, after two-step HRE at 250, 300 and 350°C were 2, 4, 7μm, respectively, resulting in superior mechanical properties at ambient temperature. The microstructure of two-step HRE was finer and uniformer than that of one-step HRE and the strength of one-step and two-step HRE were similar, moreover, the elongation of one-step HRE was improved markedly than that of two-step HRE. Dynamic recrystallization and adjacent grain broking during HRE is introduced to explain the effects of one-step and two-step HRE on the microstructure and mechanical properties of AZ31 Mg alloy. The current results imply that the simple HRE method might be a feasible processing method for industry applications, and the multiply steps extrusion are effective to fabricate high strength of fine grained hcp metals.

Effect of Cold Deformation on Microstructure and Mechanical Properties of Mg-8Gd-3Y-0.5Zr Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1297-1302
Author(s):  
De Jiang Li ◽  
Xiao Qin Zeng ◽  
Xin Su ◽  
Yan Cai Xie ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Cold Deformation ◽  
Tensile Tests ◽  
Age Hardening ◽  
Boundary Structure ◽  
Microstructure Observation ◽  
Microstructure And Mechanical Properties ◽  
Peak Aging ◽  
State 1

Pre-cold rolling with the reduction of 15% was employed on Mg-8Gd-3Y-0.5Zr (wt.%) (GW83K) alloy in different initial states: as-extruded (state 1) and extruded followed by annealing (state 2) with the aim to investigate the effects on microstructure and mechanical properties. Microstructure observation revealed that there are more amounts of mechanical twins in the alloy in state 2 than that of the alloy in state 1 after cold rolling, which indicates the different deformation mechanisms. Further investigation through EBSD has elucidated the grain boundary structure and types of twins in the alloys. Pre-cold deformation greatly promotes the age hardening response and the peak aging time at 200°C was found to be nearly 12h for the alloy in both state 1 and state 2, which were about 24h and 80h less than that of their non-deformed counterparts, respectively. Tensile tests at temperatures lower than 250°C showed that the alloy in state 1 has a predominant mechanical property than that of the alloy in state 2, while at 300°C, it displayed a reverse tendency.

Mechanical Properties of Wear Tested LIGA Nickel

2004 ◽  
Vol 841 ◽  
Author(s):  
N. R. Moody ◽  
J. M. Jungk ◽  
M. S. Kennedy ◽  
S. V. Prasad ◽  
D. F. Bahr ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Friction And Wear ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Frictional Contacts ◽  
Indentation Tests ◽  
Work Hardening Coefficient ◽  
Silicon Based ◽  
Hardening Coefficient

ABSTRACTStrength, friction, and wear are dominant factors in the performance and reliability of materials and devices fabricated using nickel based LIGA and silicon based MEMS technologies. However, the effects of frictional contacts and wear on the mechanical performance of microdevices are not well-defined. To address these effects on performance of LIGA nickel, we have begun a program employing nanoscratch and nanoindentation. Nanoscratch techniques were used to generate wear patterns using loads of 100, 200, 500, and 990 μN with each load applied for 1, 2, 5, and 10 passes. Nanoindentation was then used to measure properties in each wear pattern correcting for surface roughness. The results showed a systematic increase in hardness with applied load and number of nanoscratch passes. The results also showed that the work hardening coefficient determined from indentation tests within wear patterns follows the work hardening behavior established from tensile tests, supporting use of a nanomechanics-based approach for studying mechanical properties of wear tested material.

scholarly journals On the variability in static and cyclic mechanical properties of extruded 7075-T6 aluminum alloy

2021 ◽  
Author(s):  
Matteo Benedetti ◽  
Cinzia Menapace ◽  
Vigilio Fontanari ◽  
Ciro Santus
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Tensile Tests ◽  
Total Elongation ◽  
Extrusion Ratio ◽  
Cycle Fatigue ◽  
Hardness Tests ◽  
Fatigue Endurance

The present paper investigates the variability in the static and cyclic properties of two nominally identical supplies of the aeronautical Al grade 7075-T6. Samples were extracted from extruded bars of 15 mm and 60 mm diameter and with slightly different chemical composition. Noticeable differences were found in tensile strength, total elongation, low- and high-cycle fatigue strength, despite the nearly identical hardness value. The diverse mechanical behavior has been imputed to different extrusion ratio and therefore work hardening along with a more or less fine distribution of precipitates and dispersoids. The high-cycle fatigue strength was found to be in direct correlation with the monotonic yield strength and the size of the largest intermetallic precipitate. A simple equation based on Murakami sqrt(area) parameter is proposed to predict the fatigue endurance. Tensile tests and microstructural analyses are recommended instead of conventional hardness tests to have a tighter quality control on the mechanical properties of semifinished products.

Effect of Forward Extrusion and Heat Treatment on Microstructure and Mechanical Properties of as-Cast ZK60 Magnesium Alloy

2010 ◽  
Vol 148-149 ◽  
pp. 332-337 ◽  
Author(s):  
Yong Xue ◽  
Zhi Min Zhang ◽  
Li Hui Lang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Forward Extrusion ◽  
Zk60 Alloy ◽  
Zk60 Magnesium Alloy

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75), extrusion temperatures (300 , 340 , 380 , 420 , and 460 ), and subsequent heat treatment on the mechanical properties and microstructure of as-cast ZK60 magnesium alloy have been investigated through the tensile tests and via metallographic observation. The results show that forward extrusion process can refine the microstructure of as-cast ZK60 alloy effectively. If as-cast ZK60 alloys have been extruded with the extrusion ratio 45 at 380 ,420 and 460 , respectively, and then post-heat treatment was conducted, the ZK60 alloy’s strength is higher under T5 than T6 treatment. For as-cast ZK60 alloy processed by extrusion and T5 method, the most appropriate temperature for extrusion processing is 300 , at which its tensile strength are highest provided the extrusion ratio is 30 but yet its plasticity is best provided the extrusion ratio is 45. If forward extrusions were conducted at 380 , mechanical properties of ZK60 alloy have little difference as the extrusion ratio varies. When T6 treatment was conducted for the extruded bars, their mechanical properties were improved little, moreover, the bigger the extrusion ratio is, the higher the tensile strength and elongation of the extruded bars become.

scholarly journals Mechanical Properties of Architectured Gelatin-Based Hydrogels on Different Hierarchical Levels

MRS Advances ◽  
2016 ◽  
Vol 1 (27) ◽  
pp. 1995-2001 ◽  
Author(s):  
Radovan Vukićević ◽  
Axel T. Neffe ◽  
Tim Gebauer ◽  
Oliver Frank ◽  
Michael Schossig ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ethyl Ester ◽  
Tensile Tests ◽  
Step Process ◽  
Afm Indentation ◽  
Opposite Trend ◽  
Hierarchical Levels ◽  
One Step ◽  
Micro Level ◽  
Porous Biomaterials

ABSTRACTPreparation of three-dimensionally architectured porous biomaterials can be achieved in a one-step process by stabilizing gelatin with L-lysine diisocyanate ethyl ester (LDI) in water. The reaction of gelatin with LDI in presence of water leads to the formation of oligourea bridges between gelatin molecules and oligourea chains grafted on gelatin. The number and the length of the bridges, as well as of the grafted chains strongly depend on the concentration of the LDI used for the stabilization, and this has huge influence on the mechanical properties of the material on different hierarchical levels. Higher LDI concentrations yield materials with increased deformation resistance in tensile tests due to the higher number of covalent and physical netpoints in the material. However, mechanical properties determined on the micro-level by AFM indentation showed the opposite trend, i.e. a decrease of Young’s modulus with increasing LDI content. This was interpreted by a decreasing number of shorter oligourea bridges between gelatin chains with decreasing LDI content.

scholarly journals Microstructure and Mechanical Behavior of Mg-0.5Si-xSn Alloys

2017 ◽  
Vol 17 (4) ◽  
pp. 179-184
Author(s):  
Xuesong Fu ◽  
Yan Yang ◽  
QuanYang Ma ◽  
Xiaodong Peng ◽  
Tiancai Xu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elevated Temperature ◽  
Ultimate Tensile Strength ◽  
Temperature Stability ◽  
Tensile Tests ◽  
Extrusion Ratio ◽  
Temperature Performance ◽  
Elevated Temperature Performance ◽  
Si Content

AbstractMg-0.5Si-xSn (x=0.95, 2.9, 5.02wt.%) alloys were cast and extruded at 593K (320oC) with an extrusion ratio of 25. The microstructure and mechanical properties of as-cast and extruded test alloys were investigated by OM, SEM, XRD and tensile tests. The experimental results indicate that the microstructure of the Mg-0.5Si-xSn alloys consists of primary α-Mg dendrites and an interdendritic eutectic containing α-Mg, Mg2Si and Mg2Sn. There is no coarse primary Mg2Si phase in the test alloys due to low Si content. With the increase in the Sn content, the Mg2Si phase was refined. The shape of Mg2Si phase was changed from branch to short bar, and the size of them were reduced. The ultimate tensile strength and yield strength of Mg-0.52Si-2.9Sn alloy at the temperature of 473K (200oC) reach 133MPa and 112MPa respectively. Refined eutectic Mg2Si phase and dispersed Mg2Sn phase with good elevated temperature stability are beneficial to improve the elevated temperature performance of the alloys. However, with the excess addition of Sn, large block-like Mg2Sn appears around the grain boundary leading to lower mechanical properties.

scholarly journals Research on Extruded Products of Mgalzn Alloys – Microstructure and Mechanical Properties / Badania Wyrobów Wyciskanych Ze Stopów Mgalzn – Mikrostruktura I Właściwości Mechaniczne

2015 ◽  
Vol 60 (4) ◽  
pp. 2977-2980
Author(s):  
B. Płonka ◽  
K. Remsak ◽  
P. Korczak ◽  
M. Lech-Grega ◽  
M. Rajda
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Strength Properties ◽  
Extrusion Ratio ◽  
Test Material ◽  
Feed Speed ◽  
Direct System ◽  
Average Grain Size ◽  
Extruded Products

The aim of the study was to test and assess products extruded from the magnesium alloys type MgAlZn: AZ31, AZ61 and AZ80A alloys in the form of Ø35mm round bars and 80x15mm flat bars. The test material was extruded in a direct system with the ram feed speed of 1 mm/s and the extrusion ratio λ = 7 ÷ 9. The extruded bars were examined in as-extruded state and after heat treatment to the T5 temper and T6 temper. The strength properties were tested and microstructure was examined with calculation of the average grain size.

scholarly journals The Significance of Optimizing Mn-Content in Tuning the Microstructure and Mechanical Properties of δ-TRIP Steels

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 523
Author(s):  
Baoyu Xu ◽  
Peng Chen ◽  
Zhengxian Li ◽  
Di Wu ◽  
Guodong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Large Fraction ◽  
High Strength ◽  
Tensile Tests ◽  
Continuous Annealing ◽  
Electron Backscattered Diffraction ◽  
Trip Steels ◽  
Mn Content ◽  
Mn Steel

The δ-TRIP steel has attracted a lot of attention for its potential application in automotive components, owing to the low density, good combination of strength, and ductility. As the difficulty in yield strength further increasement is caused by large fraction ferrite, the work hardening ability was enhanced by optimizing the manganese (Mn)-content in this study. Three δ-TRIP steels with different manganese (Mn)-content were designed to explore the significant effect of Mn content on the work hardening behavior in order to develop high strength steel suitable for the industrial continuous annealing process. The detailed effect of Mn on microstructure evolution and deformation behavior was studied by scanning electron microscope (SEM), interrupted tensile tests, X-ray diffraction (XRD), and in-situ electron backscattered diffraction (EBSD). The study suggested that 2 Mn steel has the lowest degree of bainitic transformation, as a result of fine grain size of prior austenite. The large TRIP effect and dislocation strengthening improve the work hardening rate, resulting in 2 Mn steel exhibiting comparable mechanical properties with the QP980 steels. The retained austenite in 1.5 Mn steel progressively transformed into martensite and sustained the strain to a high strain value of 0.40, showing a good strength-ductility balance.

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