Mechanical Properties and Fracture Behavior of Hot Extruded Mg-5Al-3Ca-xNd Alloys at Elevated Temperature

2013 ◽  
Vol 334-335 ◽  
pp. 199-202
Author(s):  
Hyeon Taek Son ◽  
Kwang Jin Lee ◽  
Yong Hwan Kim
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Tensile Test ◽  
Intermetallic Compounds ◽  
Grain Growth ◽  
Fracture Behavior ◽  
Elevated Temperatures ◽  
Fine Grain ◽  
Nd Addition ◽  
Fracture Behaviors

In this study, effects of Nd addition on mechanical properties and fracture behaviors of as-extruded Mg-5Al-3Ca based alloy were investigated by a tensile test at elevated temperatures. For all temperatures, addition of Nd elements resulted in further increase of strength both yield and ultimate strength compared to the Mg-5Al-3Ca alloy. At 150°C, the ductility in Nd-added alloys is lower than that of no-Nd addition alloy. However, at 250°C, the ductility in Nd-added alloys is improved for no-Nd addition alloy because of fine grain and suppression of grain growth by formation of thermally stable Al2Nd intermetallic compounds.

In Situ Testing and Heterogeneity of UFG Cu at Elevated Temperatures

2015 ◽  
Vol 1127 ◽  
pp. 67-72
Author(s):  
Martin Petrenec ◽  
Petr Král ◽  
Jiří Dvořák ◽  
Milan Svoboda ◽  
Vàclav Sklenička
Keyword(s):  
Elevated Temperature ◽  
Tensile Test ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Tensile Deformation ◽  
Constant Strain Rate ◽  
Electron Back Scatter Diffraction ◽  
Coarse Grained ◽  
Ultrafine Grained

Experiments were conducted to investigate deformation-induced processes during in-situ tensile test at elevated temperature. Consequently the microstructure after creep loading was examined by 3D Electron Back Scatter Diffraction (EBSD) technique. The billets of coarse-grained copper were processed by equal-channel angular pressing (ECAP) at room temperature using a die that had an internal angle of 90° between the two parts of the channel and an outer arc of curvature of ~ 20°, where these two parts intersect. The pressing speed was 10 mm/min. To obtain an ultrafine-grained (UFG) material, the billets were subsequently pressed by route Bc by 8 ECAP passes to give the mean grain size ~ 0.7 μm. The constant strain-rate test in tension was performed at 473 K using testing GATAN stage Microtest 2000EW with EH 2000 heated grips which is configured for in-situ electron back scatter diffraction (EBSD) observations. Microstructure was examined by FEG-SEM TESCAN MIRA 3 XM equipped by EBSD detector HKL NordlysMax from OXFORD INSTRUMENT. The tensile test was interrupted by fast stress reductions after different deformation step and observation of microstructure changes was performed. Despite of a considerable interest in ECAP processing method, there are not many works documenting microstructure evolution and changes during creep testing and determining creep mechanisms of ultrafine-grained materials processed by ECAP. It was found that creep resistance of UFG pure Al and Cu is considerably improved after one ECAP pass in comparison with coarse grained material, however, further repetitive pressing leads to a noticeable deterioration in creep properties of ECAP material. Recently it was observed the coarsening of the grains in microstructure of ECAP copper during creep at elevated temperature. It was suggested that creep behaviour is controlled by storage and dynamic recovery of dislocations at high-angle boundaries. In the present work was found that ultrafine-grained microstructure is instable and significant grain growth has already occurred during heating to the testing temperature. Static recrystallization during heating led to the formation of high fraction of special boundaries Σ3 and Σ9. The tensile deformation at 473 K led to the additional grain growth and formation of new grains. Microstructure was investigated also by 3D EBSD.

Determination of Mechanical Properties for the Hydroforming of Magnesium Sheets at Elevated Temperature

2005 ◽  
Vol 6-8 ◽  
pp. 779-786 ◽  
Author(s):  
J. Hecht ◽  
S. Pinto ◽  
Manfred Geiger
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Tensile Test ◽  
Flow Curve ◽  
Elevated Temperatures ◽  
Biaxial Stress ◽  
Bulge Test ◽  
Hydraulic Bulge Test ◽  
Hydraulic Bulge

Thanks to the low weight, magnesium alloys feature high specific strength and stiffness properties. Thus they prove to be promising materials for todays ambitious automotive light weight construction efforts. Due to their comparative low formability at room temperature the process of magnesium sheet hydroforming can be improved at temperatures higher than 200 °C by the activation of additional sliding planes. This paper illustrates the determination of mechanical properties for the hydroforming of magnesium sheets at elevated temperature. In particular the mechanical behavior at elevated temperature was investigated by means of the tensile test and of the hydraulic bulge test. For the determination of the strains an optical measurement system was introduced into the experimental set-up. The exact knowledge of the strain condition in the area of diffuse necking enabled the determination of the flow curve in the tensile test also beyond the uniform elongation. The influence of temperature and strain rate was analyzed as well as the influence of uni- and biaxial stress state on the flow curve. Using circular and elliptic dies with different aspect ratio the hydraulic bulge test served to determinate the forming limit curves at three different elevated temperatures.

scholarly journals Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1473
Author(s):  
Jun Zhao ◽  
Kang Wang ◽  
Shuaibin Wang ◽  
Zike Wang ◽  
Zhaohui Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Residual Strength ◽  
Elevated Temperatures ◽  
High Volume ◽  
Sem Analysis ◽  
Geopolymer Concrete ◽  
Ordinary Concrete ◽  
Exposure Temperature

This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel (quartz and mullite, etc.) produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

MICROSTRUCTURE AND MECHANICAL BEHAVIOR OF AMORPHOUS Al–Cu–Ti METAL FOAMS SYNTHESIZED BY SPARK PLASMA SINTERING

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850022
Author(s):  
MAOYUAN LI ◽  
LIN LU ◽  
ZHEN DAI ◽  
YIQIANG HONG ◽  
WEIWEI CHEN ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Metal Foams ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Xrd Patterns

Amorphous Al–Cu–Ti metal foams were prepared by spark plasma sintering (SPS) process with the diameter of 10[Formula: see text]mm. The SPS process was conducted at the pressure of 200 and 300[Formula: see text]MPa with the temperature of 653–723[Formula: see text]K, respectively. NaCl was used as the space-holder, forming almost separated pores with the porosity of 65 vol%. The microstructure and mechanical behavior of the amorphous Al–Cu–Ti metal foams were systematically investigated. The results show that the crystallinity increased at elevated temperatures. The effect of pressure and holding time on the crystallization was almost negligible. The intermetallic compounds, i.e. Al–Ti, Al–Cu and Al–Cu–Ti were identified from X-ray diffraction (XRD) patterns. It was found that weak adhesion and brittle intermetallic compounds reduced the mechanical properties, while lower volume fraction and smaller size of NaCl powders improved the mechanical properties.

Study on the Formability of Aluminium Alloy Sheets at Room and Elevated Temperatures

2016 ◽  
Vol 877 ◽  
pp. 393-399
Author(s):  
Jia Zhou ◽  
Jun Ping Zhang ◽  
Ming Tu Ma
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Elevated Temperature ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Elevated Temperatures ◽  
Hot Stamping ◽  
Natural Aging ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet

This paper presents the main achievements of a research project aimed at investigating the applicability of the hot stamping technology to non heat treatable aluminium alloys of the 5052 H32 and heat treatable aluminium alloys of the 6016 T4P after six months natural aging. The formability and mechanical properties of 5052 H32 and 6016 T4P aluminum alloy sheets after six months natural aging under different temperature conditions were studied, the processing characteristics and potential of the two aluminium alloy at room and elevated temperature were investigated. The results indicated that the 6016 aluminum alloy sheet exhibit better mechanical properties at room temperature. 5052 H32 aluminum alloy sheet shows better formability at elevated temperature, and it has higher potential to increase formability by raising the temperature.

Friction Stir Welding of Dissimilar Formed Mg Alloys (AZ31/AZ91)

2005 ◽  
Vol 486-487 ◽  
pp. 249-252 ◽  
Author(s):  
Chang Yong Lee ◽  
Won Bae Lee ◽  
Yun Mo Yeon ◽  
Seung Boo Jung
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Tensile Test ◽  
Intermetallic Compounds ◽  
Grain Growth ◽  
Weld Zone ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Friction Stir ◽  
Az31 Mg Alloy

Friction stir welding of dissimilar formed Mg alloys(AZ31/AZ91) was successfully carried out at the limited welding conditions. In a sound joint, SZ was mainly consisted of AZ31 Mg alloy which was located the retreating side. Dynamic recrystallization and grain growth occurred and β intermetallic compounds of AZ 91 Mg alloy was not observed in SZ. BM had a higher hardness than that of the weld zone. The fracture location was not weld zone but BM of the AZ91 Mg alloy in tensile test.

Mechanical Properties of Flat Braided Composites With a Circular Hole

1999 ◽  
Author(s):  
Takeru Ohki ◽  
Shinya Ikegaki ◽  
Ken Kurasiki ◽  
Hiroyuki Hamada ◽  
Masaharu Iwamoto
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Circular Hole ◽  
Fracture Behavior ◽  
Fatigue Property ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Braided Composites ◽  
Static Tensile ◽  
The One

Abstract In this study, fracture behavior and strength in the flat braided bar with a circular hole were investigated by static and fatigue test. Two type of specimens were prepared. They are a braided flat bar with an integrally-formed braided hole and a braided flat bar with a machined hole. Moreover, we also examined a specimen that had a metal pin inserted at the circular hole. This specimen was subjected to a static tensile test. The results of the tensile tests indicate that the strength of the flat bar with a braided hole was larger than that of the one with the machined hole. Furthermore, from the results of the fatigue tests, the flat bar with the braided hole showed higher fatigue property than that of the one with the machined hole.

Fatigue responses of cracked Ti/APC-2 nanocomposite laminates at elevated temperature

2019 ◽  
Vol 54 (13) ◽  
pp. 1705-1715
Author(s):  
MHR Jen ◽  
GT Kuo ◽  
YH Wu ◽  
YJ Chen
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Composite Laminates ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Cyclic Tests ◽  
Constant Length ◽  
Nano Powder ◽  
Strength And Stiffness ◽  
Inclined Angle

The mechanical properties and fatigue responses of Ti/APC-2 neat and nanocomposites with inclined single-edged cracks due to tensile and cyclic tests at elevated temperature were investigated. Two types of composite laminates [Ti/(0/90)s/Ti] were fabricated with and without (W/WO) nanoparticles SiO2 of optimal 1 wt.%. The geometry and dimensions of specimens were L × W × t = 240 × 25 × 1.55 mm3. The cracks were of constant length 3 mm and width 0.3 mm. The inclined angles were 0°, 45°, and 60°. Both the tensile and cyclic tests were conducted at elevated temperatures 25℃ (RT), 100℃, 125℃, and 150℃. From the tensile tests we obtained the load vs. displacement curves for both types of laminates with varied inclinations at elevated temperatures. Next, we received the applied load vs. cycles curves for the same laminates with inclined cracks at the corresponding temperature due to cyclic tests. According to the experimental data of both tensile and cyclic tests the mechanical properties, such as strength, stiffness, and life, decreased as the temperature rises. The greater the inclined angles were, the greater the strength and stiffness were. Similarly, the fatigue life was in the same trend. However, the effect of inclined angle on mechanical properties was more strong than those of temperature. The mechanical properties of nanocomposite laminates were higher than those of neat composite laminates, but not significant. The main reason was that the enhancement of spreading nano-powder silica on the laminate interfaces did not effectively eliminate the stress intensity at the crack tip locally.

Mechanical Properties of Flat Braided Composites With a Circular Hole

2000 ◽  
Vol 122 (4) ◽  
pp. 420-424 ◽  
Author(s):  
Takeru Ohki ◽  
Shinya Ikegaki ◽  
Ken Kurasiki ◽  
Hiroyuki Hamada ◽  
Masaharu Iwamoto
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Circular Hole ◽  
Fracture Behavior ◽  
Fatigue Property ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Braided Composites ◽  
Static Tensile ◽  
The One

In this study, fracture behavior and strength in the flat braided bar with a circular hole were investigated by static and fatigue test. Two types of specimen were prepared. They are a braided flat bar with an integrally formed braided hole and a braided flat bar with a machined hole. Moreover, we also examined a specimen that had a metal pin inserted at the circular hole. This specimen was subjected to a static tensile test. The results of the tensile tests indicate that the strength of the flat bar with a braided hole was larger than that of the one with the machined hole. Furthermore, from the results of the fatigue tests, the flat bar with the braided hole showed higher fatigue property than that of the one with the machined hole. [S0094-4289(00)02604-9]

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