GENERATION OF SURFACE COMPOSITES AND CORROSION CHARACTERIZATION OF Mg RZ 5 ALLOY CONTAINING RARE EARTH ELEMENTS

2020 ◽  
Vol 27 (09) ◽  
pp. 1950200
Author(s):  
G. VEDABOURISWARAN ◽  
S. ARAVINDAN ◽  
P. SATHYA
Keyword(s):  
Corrosion Rate ◽  
Base Material ◽  
Friction Stir ◽  
Fine Grained ◽  
Mechanical Stirring ◽  
Surface Composites ◽  
The Matrix ◽  
Polarization Resistances ◽  
Grain Boundary Pinning

Surface composites are developed on Mg RZ 5 alloy by friction stir processing. During FSP, hard reinforcements are introduced into the matrix of RZ 5 alloy and dispersed uniformly by mechanical stirring action. The reinforcements dispersed were boron carbide, carbon nanotubes (multi-walled) and an 80:20 mixture of zirconia and alumina particles. Dynamic recrystallization and grain boundary pinning action by reinforcement particles resulted in the generation of fine-grained surface composites. Corrosion characteristics of the base material and the surface composites are studied by potentiodynamic polarization technique. The corrosion rates estimated for the surface composites are found to be far lesser than the base material while their polarization resistances were higher than the base material. Among all surface composites, B4C particle reinforced surface composites exhibited the lowest corrosion rate of [Formula: see text]15 mpy. Reduction in the corrosion rate of the surface composites is influenced by fine-grained microstructure and presence of harder reinforcement particles.

scholarly journals Characterization of Microstructural Refinement and Hardness Profile Resulting from Friction Stir Processing of 6061-T6 Aluminum Alloy Extrusions

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 552 ◽  
Author(s):  
Nelson Netto ◽  
Murat Tiryakioğlu ◽  
Paul Eason
Keyword(s):  
Friction Stir Processing ◽  
Base Material ◽  
Hardness Profile ◽  
Size Distributions ◽  
Coarse Particles ◽  
Microstructural Refinement ◽  
Friction Stir ◽  
The Matrix ◽  
Single Size

In this study, the change in microstructure and microhardness adjacent to the tool during the friction stir processing (FSP) of 6061-T6 extrusions was investigated. Results showed that the as-received extrusions contained Fe-rich constituent particles with two distinct size distributions: coarse particles in bands and finer particles in the matrix. After FSP, Fe-containing particles exhibited single-size distribution and the coarse particles appeared to be completely eliminated through refinement. Microhardness tests showed the presence of four distinct zones and that hardness increased progressively from the dynamically recrystallized closest to the tool, outward through two distinct zones to the base material. The similarities and differences between the results of this study and others in the literature are discussed in detail.

Fabrication of AA6061-0/RHA Surface Composite via Friction Stir Processing

2014 ◽  
Vol 660 ◽  
pp. 214-218 ◽  
Author(s):  
Samir Sani Abdulmalik ◽  
Rosli Ahmad
Keyword(s):  
Rice Husk ◽  
Friction Stir Processing ◽  
Rice Husk Ash ◽  
Base Material ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
Friction Stir ◽  
Mechanical Stirring ◽  
The Matrix ◽  
Surface Metal

Friction stir processing is a novel process evolved to fabricate surface metal matrix composites. Rice husk ash (RHA) is an agro-industrial waste and by product of rice husk. The feasibility of incorporating RHA powder into aluminium alloy AA6061-0 as reinforcement particles to make surface matrix composite via FSP is reported in this paper. The optical micrographs revealed a homogeneous distribution of RHA particles which were well bonded with the matrix in both first and fourth-passes of the FSP due to mechanical stirring. Microhardness of the stir zone SZ with the RHA particles of I-pass increased to about 106 HV, 40% higher than that of the base material 66 HV by dispersed RHA particles.

Microstructure of Friction Stir Processed Mg-Y-Zn Alloy

2007 ◽  
Vol 558-559 ◽  
pp. 777-780 ◽  
Author(s):  
Taiki Morishige ◽  
Masato Tsujikawa ◽  
Sung Wook Chung ◽  
Sachio Oki ◽  
Kenji Higashi
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Second Phase ◽  
Ingot Metallurgy ◽  
Friction Stir ◽  
Fine Grained ◽  
Probe Diameter ◽  
Fine Grain ◽  
Second Phase Particles ◽  
The Matrix ◽  
Zn Alloy

Friction stir processing (FSP) is the effective method of the grain refinement for light metals. The aim of this study is to acquire the fine grained bulk Mg-Y-Zn alloy by ingot metallurgy route much lower in cost. Such bulk alloy can be formed by the superplastic forging. The microstructure of as-cast Mg-Y-Zn alloy was dendrite. The dendrite arm spacing was 72.5 [(m], and there are the lamellar structures in it. FSP was conducted on allover the plate of Mg-Y-Zn alloy for both surfaces by the rotational tool with FSW machine. The stirring passes were shifted half of the probe diameter every execution. The dendrite structures disappeared after FSP, but the lamellar structure could be observed by TEM. The matrix became recrystallized fine grain, and interdendritic second phase particles were dispersed in the grain boundaries. By using FSP, cast Mg-Y-Zn alloy could have fine-grained. This result compared to this material produced by equal channel angular extrusion (ECAE) or rapid-solidified powder metallurgy (RS P/M). As the result, as-FSPed material has the higher hardness than materials produced by the other processes at the similar grain size.

Superplastic Behavior and Microstructure of Titanium (Ti-6Al-4V) Friction Stir Welds Made under a Variety of Processing Conditions

2010 ◽  
Vol 433 ◽  
pp. 169-176 ◽  
Author(s):  
Paul Edwards ◽  
Mamidala Ramulu ◽  
Daniel G. Sanders
Keyword(s):  
Friction Stir Welding ◽  
Base Material ◽  
Superplastic Forming ◽  
Spindle Speed ◽  
Processing Conditions ◽  
Superplastic Behavior ◽  
Friction Stir ◽  
Fine Grained ◽  
Weld Parameters

Friction Stir Welding of Ti-6Al-4V was performed on 5 mm thickness plate in order to assess the affect of welding conditions on the resulting microstructure and superplastic forming behavior of the joints. A variety of welding conditions were tested and all welds were subsequently Superplastically formed. It was found that the weld parameters do influence the microstructure and degree of superplastic performance of the joints. Spindle speed was found to have the most dominant affect on the resulting microstructure and superplastic forming behavior. Low spindle speed welds lead to fine grained microstructures and highly superplastic welds, relative to the base material, while high spindle speed welds larger grained microstructures and less superplastic welds.

TEM Characterization of a 7042 Aluminum FSW Joint

2012 ◽  
Vol 186 ◽  
pp. 331-334
Author(s):  
Mateusz Kopyściański ◽  
Stanislaw Dymek ◽  
Carter Hamilton
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Base Material ◽  
Friction Stir ◽  
Tem Characterization ◽  
Equiaxed Grains

This research characterizes the changes in microstructure that occur in friction stir welded extrusions of a novel 7042 aluminum alloy. Due to the presence of scandium the base material preserved the deformation microstructure with elongated grains and fairly high dislocation density. The temperature increase with simultaneous severe plastic deformation occurring during friction stir welding induced significant changes in the microstructure within the weld and its vicinity. The weld center (stir zone) was composed of fine equiaxed grains with residual dislocations and a modest density of small precipitates compared to the neighbouring thermomechanically and heat affected zones where the density of small precipitates was much higher.

Superplasticity of Friction-Stir Welded Al-Mg-Sc Alloy with Ultrafine-Grained Microstructure Obtained by Warm Severe Plastic Deformation

2016 ◽  
Vol 879 ◽  
pp. 2395-2400 ◽  
Author(s):  
Sergey Malopheyev ◽  
Sergey Mironov ◽  
Igor Vysotskiy ◽  
Rustam Kaibyshev
Keyword(s):  
Large Scale ◽  
Base Material ◽  
High Strength ◽  
Testing Temperature ◽  
Total Elongation ◽  
Friction Stir ◽  
Fine Grained ◽  
Angular Pressing ◽  
Elongation To Failure ◽  
Superplastic Properties

High-strength sheets of Al-5.4Mg-0.2Sc-0.1Zr alloy were produced by equal-channel angular pressing (ECAP) to 12 passes via route BC at 300 °C (573 K) followed by isothermal rolling at 300 °C (573 K) to a total thickness reduction of 80%. The final sheets with ultra-fine grained (UFG) structure were joined by friction stir welding (FSW). The tensile samples including all of the characteristic FSW microstructural zones were machined perpendicular to welding direction. The material demonstrated excellent superplastic properties in the range of temperatures from 350 (623 K) to 450 °C (723 K) at strain rates ranging from 8.3×10-3 s-1 to 3.3×10-1 s-1. The base material was found to be prone to abnormal grain growth at the testing temperature. This led to localization of the superplastic deformation in the stir zone section of the joints and thus limited total elongation-to-failure. The relationship between superplastic ductility and microstructure and application of this technique for the fabrication of large-scale superplastic sheets are discussed.

Mechanical Characterization of AA2024-T3 FSWed Butt Joints

2013 ◽  
Vol 753-755 ◽  
pp. 431-434 ◽  
Author(s):  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Base Material ◽  
Welding Process ◽  
Butt Joints ◽  
Influence Of Process Parameters ◽  
Rotating Speed ◽  
Friction Stir ◽  
Process Heat

In recent years friction stir welding process has received a great deal of attention from the transport industry. During the process, heat generation and material stirring induce significant microstructural alteration in the base material, affecting the properties of the welded assembly. In this paper the influence of process parameters, namely rotating speed and welding speed, on mechanical properties of AA2024-T3 friction stir butt welds is experimentally investigated. An increase of the yield stress has been found decreasing the heat input, while an opposite variation was measured for the elongation.

FABRICATION OF Mg/SiC NANOCOMPOSITE SURFACE LAYER USING FRICTION STIR PROCESSING TECHNIQUE

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1073-1076 ◽  
Author(s):  
YOONES ERFAN ◽  
SEYED FARSHID KASHANI-BOZORG
Keyword(s):  
Uniform Distribution ◽  
Friction Stir Processing ◽  
Composite Layer ◽  
Processing Technique ◽  
Speed Ratio ◽  
Friction Stir ◽  
Sic Particles ◽  
The Matrix ◽  
Tool Rotation

Friction stir processing (FSP) was employed to incorporate nano-sized SiC particles into the surface of AZ31 magnesium substrate in order to produce surface nanocomposite layers. Characterization of the microstructure of the processed layers exhibited powders agglomeration which was found to disperse with increasing the tool rotation speed/advancing speed ratio. A uniform distribution of SiC particles with a mean particle size of ~95 nm was achieved after second FSP passes. The matrix grain size was found to decrease by increasing the tool advancing speed and number of FSP passes; however, increasing the advancing speed resulted in introduction of defects which leads to tunnels. The micro hardness value of the composite layer with uniform distribution of nano-size SiC particles was found to be almost twice of that of the AZ31 substrate.

Research on Microstructure and Properties of TiB2/Al-Si Multi-Element Piston Alloy Composite

2021 ◽  
Vol 1035 ◽  
pp. 892-899
Author(s):  
Zi An Yang ◽  
Zhi Lei Xiang ◽  
Zi Yong Chen ◽  
Wei Min Ren ◽  
Zhong Hao Li ◽  
...  
Keyword(s):  
Composite Material ◽  
Master Alloy ◽  
Mass Fraction ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Base Material ◽  
Dilution Method ◽  
Mechanical Stirring ◽  
Working Temperature ◽  
The Matrix

The Al-12Si-4Cu-2Ni-0.9Mg was used as the matrix, TiB2/Al-12Si-4Cu-2Ni-0.9Mg composite material was prepared by adding Al-TiB2 in master alloy, and the mass fraction of TiB2 particles in the composite material was 3%. TiB2 particles were prepared by melt self-propagating direct synthesis method. Based on studying the influence of mechanical stirring speed on the distribution of TiB2 particles during the preparation of Al-TiB2 master alloy, the optimal mechanical stirring speed was optimized to 800 r/min. TiB2/Al-12Si-4Cu-2Ni-0.9Mg composite material was prepared by remelting and dilution method. The as-cast solidified structure of the composite material was mainly composed of α-Al matrix, Si phase and TiB2 particles, and TiB2 particles were evenly distributed. Under the condition of 360 °C(Working temperature of common piston), the tensile strength of the composite material was 15.4% higher than that of the base material, and the yield strength of the composite material was 29.4% higher than that of the base material.

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