scholarly journals Joinability of Centrifugal Composite Castings

2021 ◽  
Author(s):  
Janusz Adamiec ◽  
Katarzyna Łyczkowska ◽  
Anna Dolata ◽  
Maciej Dyzia ◽  
Klaudia Zalewska ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Aluminium Alloys ◽  
Filler Metal ◽  
Welding Process ◽  
Gradient Structure ◽  
Safe Operation ◽  
Humid Environment ◽  
Composite Casting ◽  
The Matrix ◽  
Structural Tests

Centrifugal composite castings based on aluminium alloys belong to a group of materials with high potential for application in the automotive and aerospace industries. Their use is limited by the lack of a technology enabling the obtainment of a permanent joint ensuring safe operation. The article presents the results of preliminary surfacing and welding tests of a hybrid centrifugal composite casting based on the AlSi12 alloy and reinforced with silicon carbide (5 % by weight) and glassy carbon (5 % by weight) particles. Structural tests and the quantitative evaluation of the distribution of structural constituents indicated the possibility of the joining of such composites using the TIG welding process. It was found that overlay welds made using the filler metal having a chemical composition similar to that of the matrix could be treated as a buffer layer. The aforesaid approach should enable the joining of composite castings. The structure of the weld revealed the presence of heterogeneously distributed reinforcing phases, which was related to the gradient structure of centrifugal composite castings. The presence of the Al4C3 phase at the interface between the glassy carbon and the matrix could result in the reduction of corrosion resistance in a humid environment. The structural tests discussed in the article should be supplemented with the assessment of the mechanical properties of the joint. As a result, it will be possible to implement the technology for the welding of composite castings on an industrial scale.

scholarly journals Homogenisation Efficiency Assessed with Microstructure Analysis and Hardness Measurements in the EN AW 2011 Aluminium Alloy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1211
Author(s):  
Maja Vončina ◽  
Aleš Nagode ◽  
Jožef Medved ◽  
Irena Paulin ◽  
Borut Žužek ◽  
...  
Keyword(s):  
Experimental Data ◽  
Image Analysis ◽  
Phase Equilibrium ◽  
Aluminium Alloy ◽  
Phase Formation ◽  
Aluminium Alloys ◽  
Eutectic Phase ◽  
The Matrix ◽  
Equilibrium Solidification ◽  
Homogenisation Process

When extruding the casted rods from EN AW 2011 aluminium alloys, not only their homogenized structure, but also their extrudable properties were significantly influenced by the hardness of the alloy. In this study, the object of investigations was the EN AW 2011 aluminium alloy, and the effect of homogenisation time on hardness was investigated. First, homogenisation was carried out at 520 °C for different times, imitating industrial conditions. After homogenisation, the samples were analysed by hardness measurements and further characterised by microscopy and image analysis to verify the influence of homogenisation on the resulting microstructural constituents. In addition, non-equilibrium solidification was simulated using the program Thermo-Calc and phase formation during solidification was investigated. The homogenisation process enabled more rounded shape of the Al2Cu eutectic phase, equilibrium formation of the phases, and the precipitation in the matrix, leading to a significant increase in the hardness of the EN AW 2011 aluminium alloy. The experimental data revealed a suitable homogenisation time of 4–6 h at a temperature of 520 °C, enabling optimal extrusion properties.

The Investigation on Aluminium Alloys Automobile Wheel with Low-Titanium Content Produced by Electrolysis

2005 ◽  
Vol 475-479 ◽  
pp. 317-320 ◽  
Author(s):  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Zhong Xia Liu ◽  
Ai Qin Wang ◽  
Yong Gang Weng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminium Alloys ◽  
Solution Treatment ◽  
A356 Alloy ◽  
Aging Treatment ◽  
Titanium Content ◽  
The Matrix ◽  
Automobile Wheel

The in-situ Ti alloying of aluminium alloys was fulfilled by electrolysis, and the material was made into A356 alloy and used in automobile wheels. The results show that the grains of the A356 alloy was refined and the second dendrites arm was shortened due to the in-situ Ti alloying. Trough 3-hour solution treatment and 2-hour aging treatment for the A356 alloy, the microstructures were homogeneous, and Si particles were spheroid and distribute in the matrix fully. The outstanding mechanical properties with tensile strength (σb≥300Mpa) and elongation values (δ≥10%) have been obtained because the heat treatment was optimized. Compared with the traditional materials, tensile strength and elongation were increased by 7.6~14.1% and 7.4~44.3% respectively. The qualities of the automobile wheels were improved remarkably.

scholarly journals The Effect of Copper and Brass on Friction Stir Welded Dissimilar Aluminium Alloy When Used as in Thin Sheet Form

2016 ◽  
Vol 45 (2) ◽  
pp. 118-122
Author(s):  
G. Gopala Krishna ◽  
P.Ram Reddy ◽  
M.Manzoor Hussain
Keyword(s):  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Low Cost ◽  
Thin Sheet ◽  
Welding Process ◽  
Cost Effective ◽  
Tensile Tests ◽  
Fusion Welding ◽  
Friction Stir ◽  
Effect Of Copper

In recent year’s aluminium and aluminium alloys are most widely used in many applications because of light weight, good formability and malleability, corrosion resistance, moderate strength and low cost. Friction Stir Welding (FSW) process is efficient and cost effective method for welding aluminium and aluminium alloys. FSW is a solid state welding process that means the material is not melted during the process. Complete welding process accomplishes below the melting point of materials so it overcomes many welding defects that usually happens with conventional fusion welding technique which were initially used for low melting materials. Though this process is initially developed for low melting materials but now process is widely used for a variety of other materials including titanium, steel and also for composites. The present butt jointed FSW experimental work has been done in two ways. Initially a comparison of tensile properties of friction stir (FS) welded similar aluminium alloy (AA6351 with AA6351) and dissimilar aluminium alloy (AA6351 with AA5083) combinations. Later the effect of impurities (copper and brass) in sheet form (0.1 mm thick) when used as insert in between two dissimilar aluminium alloy (AA6351 with AA5083) plates during FSW. Tensile tests were performed for these combinations and results were compared for with and without using strip material (copper and brass).

Impact of Tin and Nickel on the Brazing Properties of Silver Filler Metals and on the Strength of Brazed Joints Made of Stainless Steels

2013 ◽  
Vol 58 (4) ◽  
pp. 1007-1011 ◽  
Author(s):  
A. Winiowski ◽  
M. Rózanski
Keyword(s):  
Stainless Steels ◽  
Shear Test ◽  
Filler Metal ◽  
Positive Impact ◽  
Energy Dispersive Spectrometer ◽  
Light And Electron Microscopy ◽  
Vacuum Brazing ◽  
Brazed Joints ◽  
Structural Tests ◽  
Filler Metals

Abstract The research involved vacuum tests of brazing properties of silver filler metals, containing tin as well as tin and nickel, and used in brazing of chromium X6Cr17 and chromium-nickel X6CrNiTi18-10 stainless steels. The research also involved testing the strength and structural properties of brazed joints made of these steels. The tests were conducted on filler metals (silver brazing alloys) B-Ag68CuSn-730/755 (Ag68Cu28Sn4) and B-Ag65CuSnNi-740/767 (Ag65Cu28Sn5Ni2) and also, for comparative purposes, on the filler metal B-Ag72Cu-780 (Ag 272 according to PN-EN ISO 17672), most commonly applied in the vacuum brazing of high alloyed stainless steels. The brazing properties of the filler metals were tested by determining their wettability by means of the spreadability method. The strength of brazed joints made of the stainless steels was examined in a shear test. Research-related structural tests involved light and electron microscopy with an energy dispersive spectrometer (EDS). The comparative analysis of the properties of the filler metals revealed the positive impact of tin and nickel on the spreadability and wettability of the silver brazing alloys as well as on the quality and the shear strength of brazed joints.

Effect of Tool pin Profile and Axial Force on Tensile Behavior in Friction Stir Welding of Dissimilar Aluminum Alloys

2011 ◽  
Vol 415-417 ◽  
pp. 1140-1146 ◽  
Author(s):  
R. Palanivel ◽  
P. Koshy Mathews ◽  
M. Balakrishnan ◽  
I. Dinaharan ◽  
N. Murugan
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Axial Force ◽  
Aluminium Alloys ◽  
Welding Process ◽  
Fusion Welding ◽  
Friction Stir ◽  
Tool Pin Profile ◽  
Dissimilar Aluminum Alloys ◽  
Tool Pin

Aluminium alloys generally has low weldability by traditional fusion welding process. The development of the Friction Stir Welding (FSW) has provided an alternative improved way of producing aluminium joints, in a faster and reliable manner. FSW process has several advantages, in particular the possibility to weld dissimilar aluminium alloys. This study focuses on the behavior of tensile strength of dissimilar joints of AA6351-T6 alloy to AA5083-H111 alloy produced by friction stir welding was analysed. Five different tool pin profile such as Straight Square (SS), Tapered Square (TS), Straight Hexagon (SH), Straight Octagon (SO) and Tapered Octagon (TO) with three different axial force (1tonne, 1.5tonne, 2 tonne) have been used to weld the joints. The effect of pin profiles and axial force on tensile properties and material flow behaviour of the joint was analyzed and it was found that the straight square pin profile with 1.5 tonne produced better tensile strength then other tool pin profile and axial force.

Linear Friction Welding of IN-718 Process Optimization and Microstructure Evolution

2006 ◽  
Vol 15-17 ◽  
pp. 357-362 ◽  
Author(s):  
Caroline Mary ◽  
Mohammad Jahazi
Keyword(s):  
Process Parameters ◽  
Microstructure Evolution ◽  
Friction Welding ◽  
Welding Process ◽  
Weld Interface ◽  
Maximum Temperature ◽  
Linear Friction Welding ◽  
Influence Of Process Parameters ◽  
Linear Friction ◽  
The Matrix

Linear Friction Welding (LFW) of IN-718 Superalloy was investigated under several processing conditions. The influence of process parameters such as frequency (60Hz to 100Hz), amplitude (2mm to 3mm) and frictional pressure (50MPa to 110MPa) on the microstructure and mechanical properties of welded specimens was determined. Optical and scanning electron microscopy, and micro-hardness testing were used to characterize the welded areas as well as the Thermo-Mechanically Affected Zones (TMAZ). In-situ thermocouple measurements were performed to follow temperature evolution in the specimens during the different phases of the LFW process. The analysis of the results indicated that for some specific conditions (f=80Hz, a=2mm and P=70MPa) a maximum temperature of 1200°C was attained during the last stage of the welding process, the burn-off phase. This temperature, very close to the alloy melting range, would be sufficient to cause partial liquation in this zone. Microscopic examinations revealed the presence of oxide particles aligned around the weld interface. Their concentration and distribution, varying with process parameters, affect the weld integrity. The TMAZ characterised by a global loss of strength (from 334HV to 250HV) is associated with temperatures exceeding 800°C and causing γ’ and γ’’ reversion. A narrow band of the TMAZ, exposed to high strains and temperatures, showed evidences of dynamic recovery and recrystallization (up to 67% of reduction in the matrix grain size). Visual and microscopic examination of the flash layer, revealed two distinct zones. Microstructure evolution and microhardness variations were associated to process parameters and the optimum conditions for obtaining defect free weldments were determined.

The emission spectroscopy of some elements in high-temperature flames

1979 ◽  
Vol 44 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Marie Pištěková ◽  
Jaroslav Jambor ◽  
Vítězslav Otruba ◽  
Lumír Sommer
Keyword(s):  
High Temperature ◽  
Atomic Absorption ◽  
Aluminium Alloys ◽  
Emission Spectroscopy ◽  
Scattered Light ◽  
Good Resolution ◽  
Matrix Elements ◽  
Chemical Interference ◽  
The Matrix ◽  
Small Chemical

The emission of atoms of a large number of elements in laminar high-temperature acetylene-N2O, H2-N2O, H2-O2, acetylene-air, and H2-air flames was studied; of these the most suitable are flame mixtures containing N2O. Methods were developed for determining Ca, Sr, Ba, for Cu, Cr, Mn and Ni in steels and for Cu, Fe, Mn and Ni in aluminium alloys using an acetylene-N2O flame. A small chemical interference for the matrix elements was found provided that a monochromator with good resolution and with a small amount of scattered light was employed. These conditions are fulfilled by most modern atomic absorption instruments with which comparable results are obtained.

Thermal Expansion Behavior of the Multiphase Composite System

2004 ◽  
Vol 449-452 ◽  
pp. 765-768
Author(s):  
Chong Sung Park ◽  
Hyun Seok Hong ◽  
Myung Ho Kim ◽  
Chong Mu Lee
Keyword(s):  
Thermal Expansion ◽  
Composite System ◽  
Welding Process ◽  
High Volume ◽  
Volume Percent ◽  
New Approach ◽  
Composite Systems ◽  
Expansion Behavior ◽  
The Matrix ◽  
Multiphase Composite

A new approach for the CTE on the basis of Ashelby.s cutting and welding process was made for the analysis of the thermal expansion behaviors of Al-Si alloys and composites. In this theoretical approach, it was considered that relaxation of residual stress could create an elastoplastic zone in the matrix around a particle during cooling. A comparison of the measured CTEs with the calculated ones for the Al-Si-SiCp and Al-Si-Al2O3 composite systems was performed in terms of the volume percent and the size of reinforced phases. The calculated results revealed that the linear CTE of the both composite depends on the size of the reinforce phases, especially at the composite systems with a low volume percent of the reinforce phases. The increase in the volume percentages of Al2O3, SiCp and Si phase lowers the linear CTEs of the systems. The measured CTEs was deviated less than about ten percents from the calculated ones at composites with a high volume percent. The deviations of the CTEs of reinforced phases are about 4 - 6 vol% from real composite systems.

Case Study on LBB Application for Field Fabrication Weld Metal of Nuclear Primary Piping Systems

2003 ◽  
Author(s):  
K. C. Kim ◽  
J. T. Kim ◽  
J. I. Suk ◽  
H. K. Kwon ◽  
U. H. Sung ◽  
...  
Keyword(s):  
Weld Metal ◽  
Carbon Content ◽  
Arc Welding ◽  
Filler Metal ◽  
Welding Process ◽  
Test Results ◽  
Fracture Characteristics ◽  
Reactor Coolant ◽  
Piping Systems ◽  
Arc Welding Process

In order to apply leak before break (LBB) design for nuclear primary piping systems, dynamic and static J-R tests of field fabrication weld metal were carried out to determine mechanical properties at 316°C. For the reactor coolant piping system made by SMAW (Shielded Metal Arc Welding) process of the SA508 Cl.1a, the variation of J-R fracture characteristics with the loading rate of 1mm/min and 1,000mm/min was examined to prevent the catastrophic break under seismic loading. In the J-R test results, the J-R curves at 1,000mm/min are about 60% higher than those at 1mm/min. It suggests that the welding joints of the reactor coolant piping may be susceptible to dynamic strain aging at 316°C. For the surge line piping made by GTAW (Gas Tungsten Arc Welding) process of the SA312 TP347, excellent static J-R properties are required because the nominal diameter of the pipe is relatively small size of 12 inch. In order to examine the effect of carbon content in the filler metal on the fracture toughness of its welded metal, weld metal specimens were made by using 3 kinds of filler metals whose carbon contents were 0.050, 0.030 and 0.025%, respectively. In the static J-R test results, weld metal made by one of three electrodes satisfied the LBB acceptance criteria. Much better J-R fracture characteristics with decreasing carbon content of filler metal can be shown.

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