scholarly journals Effect of Micro-Scale Er on the Microstructure and Fluidity of ZL205A Alloy

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1688 ◽  
Author(s):  
Tingbiao Guo ◽  
Bing Wang ◽  
Zhanfei Zhang ◽  
Quanzhen Sun ◽  
Yuhua Jin ◽  
...  
Keyword(s):  
Energy Dispersive Spectrometer ◽  
Fracture Morphology ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Fracture Characteristics ◽  
X Ray ◽  
Micro Scale ◽  
Heat Treated ◽  
Zl205a Alloy ◽  
Increasing Precipitation

The effect of Er addition on the fluidity and microstructure transformation of the as-cast and T5 heat-treated ZL205A alloys was investigated by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). The fluidity of the liquid metal after adding Er was tested and the fracture characteristics of the material were analyzed. The results indicated that Er was mainly dissolved into an α–Al matrix near the grain boundaries (GBs). It is easily segregated and enriched in the intersection of the GBs or the interface between the α and θ phase, which caused the intermetallic compounds to be distributed along the GBs to the neck and to fuse. Er could also inhibit the diffusion of Cu atoms in the process of solid solution, so that increased the residual eutectic structures in the crystal, while accelerating the precipitation progress of the Guinier–Preston (GP) zone and θ’ phase and increasing precipitation of the θ phase. A small amount of precipitation of θ phase and micro-scale Er (0.1–0.5 wt %) can significantly increase the fluidity and reduce the casting defects, which can effectively improve the castability of the ZL205A alloy. The interface between the (Al8Cu4Er) phase and matrix is the main area of microcracks, through analyzing the fracture morphology.

Study on Atmospheric Corrosion Behaviour of Sicp/Al Composite

2010 ◽  
Vol 136 ◽  
pp. 275-278
Author(s):  
Xian Liang Zhou ◽  
Duo Sheng Li ◽  
Ai Hua Zou ◽  
Xiao Zhen Hua ◽  
G.Z. Ye ◽  
...  
Keyword(s):  
Atmospheric Corrosion ◽  
Corrosion Behaviour ◽  
Energy Dispersive Spectrometer ◽  
Optical Microscope ◽  
Atmospheric Environment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Composite ◽  
Amorphous Al2o3 ◽  
Scanning Electron

SiCp/Al composite was fabricated by the method of pressureless-infiltration. In atmospheric environment, the atmospheric corrosion behavior of SiCp/Al composites (ZL101+49%SiC+5%Mg) was studied by mass loss, optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR), respectivelhy.The results show that the corrosion rate of the SiCp/Al composites increases with increasing of time in atmospheric environment. Pitting corrosion is the main characteristic of SiCp/Al composite, and corrosion area gradually extends around with time increasing. At last, sheet like corrosion substrates distribute in the surface of n the SiCp/Al composites. Amorphous Al2O3 and amorphous AlxSO4yOHz are the main corrosion products.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

scholarly journals Extraction of Boron from Ludwigite Ore: Mechanism of Soda-Ash Roasting of Lizardite and Szaibelyite

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Energy Dispersive Spectrometer ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selective Activation ◽  
X Ray ◽  
Shed Light ◽  
Soda Ash ◽  
Scanning Electron

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.

PREPARATION OF ANTIMONY-PLATINUM SURFACE ALLOY ELECTRODE BY ATOM DIFFUSION IN THE SOLID PHASE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3999-4004
Author(s):  
HIROSHI MATSUI ◽  
KAZUFUMI WATANABE
Keyword(s):  
Diffraction Pattern ◽  
Low Temperatures ◽  
Solid Phase ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Platinum Surface ◽  
X Ray ◽  
Atom Diffusion ◽  
Heat Treated ◽  
Titanium Substrates

Antimony-platinum bilayers were prepared on titanium substrates by the two-step electrodeposition in the usual baths, and then surface alloys were formed by the atom diffusion in the solid phase. The simple antimony layer was little influenced by the substrate in both the measurements of X-ray diffraction and the i - E characteristic in a sulfuric acid solution. Regarding the bilayers, the catalytic activity in hydrogen evolution reaction was very sensitive to the presence of platinum, while the hydrogen adsorbability was quite insensitive. An interaction between antimony and platinum was confirmed by the appearance of a new dissolution wave in the electrochemical measurement and the occurrence of a new diffraction in the X-ray diffraction pattern after the heat-treatment of about 400°C. Although the new diffraction disagreed with any of the reported alloys, clear diffraction pattern of PtSb 2 alloy was observed, when the bilayers were heat-treated at about 600°C for one hour. Considering the penetration depth of X-ray, the alloying of antimony and platinum seems to occur also at low temperatures at least at the top surface.

Hardening of Selective Laser Melted M2 Steel

2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
High Hardness ◽  
Steel Part ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Near Net Shape

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.

X-Ray Diffraction Analysis on Crystallite Development of Nanostructured Aluminium

2006 ◽  
Vol 118 ◽  
pp. 53-58
Author(s):  
Elisabeth Meijer ◽  
Nicholas Armstrong ◽  
Wing Yiu Yeung
Keyword(s):  
Crystallite Size ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Equal Channel Angular Extrusion ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Heat Treated ◽  
Diffraction Peaks

This study is to investigate the crystallite development in nanostructured aluminium using x-ray line broadening analysis. Nanostructured aluminium was produced by equal channel angular extrusion at room temperature to a total deformation strain of ~17. Samples of the extruded metal were then heat treated at temperatures up to 300oC. High order diffraction peaks were obtained using Mo radiation and the integral breadth was determined. It was found that as the annealing temperature increased, the integral breadth of the peak reflections decreased. By establishing the modified Williamson-Hall plots (integral breadth vs contract factor) after instrumental correction, it was determined that the crystallite size of the metal was maintained ~80 nm at 100oC. As the annealing temperature increased to 200oC, the crystallite size increased to ~118 nm. With increasing annealing temperature, the hardness of the metal decreased from ~60 HV to ~45 HV.

Microstructure and Hardness of Ni-Cr Porous Preform Reinforced Al-Based Composites by Low Infiltration Method

2011 ◽  
Vol 275 ◽  
pp. 251-254
Author(s):  
Hua Wei Rong ◽  
Cheol Hong Park ◽  
Won Jo Park ◽  
Han Ki Yoon
Keyword(s):  
Intermetallic Compounds ◽  
Rapid Development ◽  
High Hardness ◽  
Optical Microscope ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Infiltration Process ◽  
Pressure Infiltration ◽  
X Ray ◽  
Infiltration Method

With the rapid development of aerospace and automobile industries, metal matrix composites (MMCs) have attracted much attention because of its excellent performance. In this paper, Ni-Cr/AC8A composites reinforced with porous Ni-Cr preform were manufactured by low pressure infiltration process, infiltration temperatures are 700oC~850oC. The microstructure and phase composition of composites were evaluated using optical microscope, X-ray diffraction (XRD) and electro-probe microanalysis (EPMA), It's found that they're intermetallic compounds generated in the composites. Recently, intermetallic compounds have attracted much attention as high-temperature material. We study the hardness of Ni-Cr/AC8A composites, the results show the Ni-Cr/AC8A composite has high hardness due to the intermetallic compounds exist.

Effect of Pressure Carbonization in Carbon/Carbon Composite Process (II)

1991 ◽  
Vol 251 ◽  
Author(s):  
H. Okamoto ◽  
T. Hosomura ◽  
K. Kosaka
Keyword(s):  
Iron Powder ◽  
Phenolic Resin ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
Micro Structure ◽  
Carbon Yield ◽  
X Ray ◽  
Effect Of Pressure ◽  
Heat Treated ◽  
Powder Addition

ABSTRACTWe have found that pressurized carbonization cause the increase of carbon yield and the improvement of micro structure In the case of pitch resin. While the effects of pressurized carbonization on phenolic resin are not obvious.In this study, carbonization and graphitization characteristics of phenolic resin were investigated experimentally. Phenolic resin specimens with and without iron powder addition were carbonized at the temperature of 650 °C under the pressure of atmospheric or 100MPa. Then each of them was heat-treated at the temperature of 1200, 1500 and 1900 °C respectively. Measurement of yield, density, x-ray diffraction and optical observation were carried out in the experiments. It is indicated from those results that pressurized carbonization of phenolic resin makes graphite crystallization progress and this effect is promoted by addition of iron powder.

scholarly journals Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

Cerâmica ◽  
2016 ◽  
Vol 62 (364) ◽  
pp. 386-391 ◽  
Author(s):  
J. R. M. Ferreira ◽  
L. H. L. Louro ◽  
A. M. Costa ◽  
J. B. de Campos ◽  
M. H. Prado da Silva
Keyword(s):  
Xrd Analysis ◽  
Quantitative Chemical Analysis ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Heat Treated ◽  
Before And After ◽  
Calcium Source ◽  
The Fourier Transform ◽  
Ostrich Eggshell

Abstract In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Ni-B-W-Mo COATING DEPOSITED BY ELECTROLESS METHOD

2018 ◽  
Vol 25 (08) ◽  
pp. 1950023 ◽  
Author(s):  
ARKADEB MUKHOPADHYAY ◽  
TAPAN KUMAR BARMAN ◽  
PRASANTA SAHOO
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Sodium Molybdate ◽  
Medium Carbon Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Heat Treated ◽  
Electroless Coatings

The present work reports the deposition of a quaternary Ni-B-W-Mo coating on AISI 1040 medium carbon steel and its characterization. Quaternary deposits are obtained by suitably modifying existing electroless Ni-B bath. Composition of the as-deposited coating is analyzed by energy dispersive X-ray spectroscopy. The structural aspects of the as-deposited and coatings heat treated at 300[Formula: see text]C, 350[Formula: see text]C, 400[Formula: see text]C, 450[Formula: see text]C and 500[Formula: see text]C are determined using X-ray diffraction technique. Surface of the as-deposited and heat-treated coatings is examined using a scanning electron microscope. Very high W deposition could be observed when sodium molybdate is present in the borohydride-based bath along with sodium tungstate. The coatings in their as-deposited condition are amorphous while crystallization takes place on heat treatment. A nodulated surface morphology of the deposits is also observed. Vickers’ microhardness and crystallite size measurement reveal inclusion of W and Mo results in enhanced thermal stability of the coatings. Solid solution strengthening of the electroless coatings by W and Mo is also observed. The applicability of kinetic strength theory to the hardening of the coatings on heat treatment is also investigated. Corrosion resistance of Ni-B-W-Mo coatings and effect of heat treatment on the same are also determined by electrochemical techniques.

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