Effect of Two-Step Aging Process on Microstructure and Fracture Toughness of 7085 Aluminum Alloy

2016 ◽  
Vol 852 ◽  
pp. 149-155
Author(s):  
Yang Song ◽  
Bai Qing Xiong ◽  
Yong An Zhang ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Aluminum Alloy ◽  
Aging Process ◽  
Treatment Time ◽  
Aging Treatment ◽  
Free Zone ◽  
Intergranular Failure ◽  
Transmission Electron ◽  
Fracture Morphologies

In this paper, the effect of two-step aging treatment on microstructure and fracture toughness of 7085 aluminum alloy were investigated by using tear tests to carry out the fracture toughness tests of the alloy and using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to analyze the microstructure. The results showed the main precipitates in the alloy were GP zones and η' phases in the grains after 118°C/6h aging treatment. With further secondary aging treatment, grain boundaries precipitates (GBPs) grew up, and the precipitate-free zone (PFZ) showed up, the increasing proportion of intergranular failure was occurred and the fracture toughness decreased. With further prolonging of the secondary aging treatment time, precipitates in the grains tended to be coarser, the GBPs became discontinuous ,PFZ became wider, and there were decreasing proportion of the intergranular failure and increasing proportion of the transgranular failure showing on the fracture morphologies, the fracture toughness of 7085 aluminum alloy increased.

Effect of Cold Deformation on Precipitation of 7050 Aluminum Alloy during Aging Process

2015 ◽  
Vol 1120-1121 ◽  
pp. 1014-1018
Author(s):  
Hong Wei Yan ◽  
Liang Zhen ◽  
Jian Tang Jiang
Keyword(s):  
Electron Microscopy ◽  
Aluminum Alloy ◽  
Aging Process ◽  
Cold Deformation ◽  
Research Topic ◽  
Strengthening Mechanisms ◽  
Scanning Calorimetry ◽  
Main Research ◽  
Transmission Electron ◽  
7050 Aluminum Alloy

Strengthening of aluminum alloy has always been an interesting research topic. There might be interactions between different strengthening mechanisms. In this paper, the effect of large cold deformation on the precipitation of as-quenched 7050 aluminum alloy was studied. Differential scanning calorimetry was used as the main research technique, accompanied by tensile test and transmission electron microscopy. It was found that clusters and precipitation had formed in the cold deformation, and dislocations accelerated the precipitation dynamics.

scholarly journals Effects of Aging on the Microstructure and Properties of 7075 Al Sheets

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4022
Author(s):  
Zhongxin Zhao ◽  
Ruoqing Wu ◽  
Bo Wang ◽  
Mingchu Huang ◽  
Guopeng Lei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Treatment Time ◽  
Aging Treatment ◽  
Strength Properties ◽  
Double Aging ◽  
Transmission Electron ◽  
One Step ◽  
The One ◽  
Effects Of Aging ◽  
Working Efficiency

The effects of one-step aging and double aging on the properties and microstructures of 7075 Al sheets were studied via mechanical property testing, scanning electron microscopy, and transmission electron microscopy. The results indicated that with continued one-step aging, the tensile and yield strengths of the Al sheets first increased rapidly with an increase in the treatment time to 8 h and then increased slightly with a further increase in the treatment time to 10 h. The tensile and yield strengths became constant after 16 h of treatment. The mechanical strength properties of the Al sheets peaked after 16 h of one-step aging. However, the double aging treatment provided better mechanical properties and working efficiency than the one-step aging treatment. The tensile strength and microhardness resulting from double aging were greater than those resulting from one-step aging by 5.87% and 8.71%, respectively. Herein, we quantified the contribution ofvarious strengthening mechanisms.

Effect of Aging Treatment on Microstructure and Mechanical Properties of a Two-Phase Titanium Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 851-854
Author(s):  
Miao Song ◽  
Jia Feng Lei ◽  
Ying Jie Ma ◽  
Yu Yin Liu
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Quantitative Analysis ◽  
Aging Temperature ◽  
Aging Treatment ◽  
Large Area ◽  
Two Phase ◽  
Rich Phase ◽  
Α Phase ◽  
Transmission Electron

In present work, microstructure of Ti-6Al-2Mo-1.5Cr-2Sn-2Zr-1V-0.15Si-0.4Fe alloy as a function of aging temperature was investigated using optical microscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM).Three types of precipitates were found in this alloy, they were α2 phase (Ti3Al), silicides, and Sn rich phase. Ti3Al were observed in all aged specimens covering a range 500-740°C. A method of quantitative analysis toward α2 based on high resolution images and Flourier transformation is used. The results showed that the ordering in α phase was highly related to the property of fracture toughness. Silicides were first found at 580°C ageing and later determined in the formulate (Ti5+xZr3-x)Si3 in the specimens aged at 740°C, and they were found to influent the fracture toughness significantly. The Sn rich phase was emerged with large area during the 780°C aging. And its direct correlation to property was not found. The density of acicular α phase was found almost invariable by calculating through the modification XRD quantitative analysis during the elevated aging temperature.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

The Effect of Aging Heat Treatment on the Microstructure and Mechanical Properties of 10Cr20Ni25Mo1.5NbN Austenitic Steel

2016 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Zhiyuan Liang ◽  
Wanhua Sha ◽  
Qinxin Zhao ◽  
Chongbin Wang ◽  
Jianyong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Austenitic Steel ◽  
Treatment Time ◽  
Aging Treatment ◽  
Secondary Phases ◽  
Aging Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
The Impact

AbstractThe effect of aging heat treatment on the microstructure and mechanical properties of 10Cr20Ni25Mo1.5NbN austenitic steel was investigated in this article. The microstructure was characterized by scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy. Results show that the microstructure of 10Cr20Ni25Mo1.5NbN austenitic is composed of austenite. This steel was strengthened by precipitates of secondary phases that were mainly M23C6 carbides and NbCrN nitrides. As aging treatment time increased, the tensile strength first rose (0–3,000 h) and then fell (3,000–5,000 h) due to the decrease of high density of dislocations. The impact absorbed energy decreased sharply, causing the sulfides to precipitate at the grain boundary. Therefore, the content of sulfur should be strictly controlled in the steelmaking process.

A novel additive-free oxides–hydrothermal approach for monazite-type LaPO4nanomaterials with controllable morphologies

2010 ◽  
Vol 43 (5) ◽  
pp. 990-997 ◽  
Author(s):  
Jie Ma ◽  
Qingsheng Wu
Keyword(s):  
Electron Microscopy ◽  
Treatment Time ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Hydrothermal Conditions ◽  
Typical Sample ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Hydrothermal Approach

A facile oxides–hydrothermal (O–HT) method is demonstrated to prepare high-purity monazite-type LaPO4nanomaterials. In this approach, La2O3and P2O5powder are first directly used as precursors under additive-free hydrothermal conditions. The as-prepared samples are characterized with X-ray diffraction, Fourier transform IR spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy (high-resolution TEM, energy dispersive spectroscopy) and selected-area electron diffraction. The typical sample obtained at 433 K in 24 h comprises uniform single-crystal nanofibres with a diameter of ∼15–28 nm and an aspect ratio of 30–50. The influences of treatment time, synthesis temperature and P/La molar ratio are investigated. The phase transition from hexagonal hydrate to monoclinic anhydrous lanthanum phosphate and the growth process of nanofibres are revealed by the experimental results. The formation mechanism of the monoclinic LaPO4is discussed. The result indicates that the P/La ratio does not influence the composition and crystal phase but changes the morphology of the product in the O–HT system.

scholarly journals Influence of Thermal Aging Parameters on the Characteristics of Aluminum Semi-Solid Alloys

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 746 ◽  
Author(s):  
Khaled Ragab ◽  
Mohamed Bouazara ◽  
Xiao Chen
Keyword(s):  
Electron Microscopy ◽  
Aluminum Alloys ◽  
Thermal Aging ◽  
Aging Treatment ◽  
Load Variations ◽  
Transmission Electron ◽  
Semisolid Alloys ◽  
Automotive Parts ◽  
Semi Solid ◽  
Solid Alloys

The current study aimed at analyzing the response of semisolid A357 aluminum alloys to unconventional thermal treatment cycles of T4/T6/T7 conditions. The mechanical, electrical, and microstructural characterizations of such semisolid alloys were investigated. The microstructure evolutions of Fe-intermetallic phases and strengthening precipitates were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The mechanical failure of such semi solid A357 aluminum alloys, used for suspension automotive parts, is mostly related to cracking issues which start from the surface due to hardness problems and propagate due to severe load variations. For these reasons, the multiple thermal aging cycles, in this study, are applied to enhance the mechanical properties and to have compromised values compared to those obtained by standard thermal treatments. The results obtained in this work indicate that the heat treatment of this alloy can be optimized. The results showed that the optimum characteristics of A357 semisolid alloys were obtained by applying thermal under-aging cycle, interrupted thermal aging cycles and a T7/T6 two steps aging treatment condition. The electrical conductivity and electron microscopy were applied in this study to analyze the characteristics of hardening phases formed due to different aging cycles applied to the alloys investigated.

scholarly journals The sintering kinetics of shellfish porcelain reinforced by sepiolite nanofibres

2018 ◽  
Vol 5 (10) ◽  
pp. 180483 ◽  
Author(s):  
Li Tian ◽  
Lijuan Wang ◽  
Kailei Wang ◽  
Yuedan Zhang ◽  
Jinsheng Liang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Diffusion Mechanism ◽  
Linear Shrinkage ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Fibre Pullout ◽  
Sintering Behaviour

The work investigated the effect of sepiolite nanofibres on mechanical properties and sintering behaviour of shellfish porcelain. Samples of shellfish porcelain reinforced by sepiolite nanofibres were fired in an electric furnace at 1150, 1200 and 1250°C for a period of 80, 100, 120 and 140 min. Sintered samples were characterized by flexural strength, fracture toughness, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results showed that 2 wt% sepiolite nanofibres could increase the flexural strength and fracture toughness of the porcelain bodies through the fibre pullout and the weak interface mechanisms. Sintering activation energies were determined according to the linear shrinkage results. It is found that the liquid-phase sintering mechanism of shellfish porcelain with sepiolite nanofibres is a diffusion mechanism. Porcelain without sepiolite is controlled by volume diffusion, and eventually, the grain boundary diffusion began to appear with the increase of sepiolite addition.

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