scholarly journals An Investigation of corrosion of friction welded and post-weld heat-treated AA6061/SiC/graphite hybrid composites

2021 ◽  
Vol 61 (3) ◽  
pp. 456-464
Author(s):  
Jadamuni Senthilkumar ◽  
Pavan S. M. Kumar ◽  
Manickam Balasubramanian

The aluminium-based hybrid metal matrix composites have noteworthy applications in sub-sea installations, structures of deep-sea crawlers, submarine parts, engine cylinders, drum brakes etc., as they possess high strength, corrosion resistance, chemical, and dimensional stability. In this investigation, the pitting corrosion behaviour of friction welded and post-weld heat-treated AA6061/SiC/graphite hybrid composites were analysed. The corrosion rates of AW (as welded), ST (Solution treated), STA (Solution treated and Aged), and AA (Artificially Aged) weld joints were experimentally determined. The corrosion behaviour has been discussed in light of microstructure. The experimental results revealed that the STA joints exhibited better corrosion resistance characteristics as compared to AW, AA, and ST joints. The corrosion rate was high for AW joints, followed by AA and ST joints, respectively. Taking into account the corrosion rates of AW and STA joints, the STA joints have a corrosion rate 34.6% lesser than that of AW joints. A comparison of AA and ST with STA joints reveals that the rate of corrosion for STA joints was 31.1% lesser than that of AA joints and 28.8% lesser than that of ST joints. A lower corrosion rate was observed for STA joints as compared to AA, AW, and ST joints.

2019 ◽  
Vol 3 (2) ◽  
pp. 1-8
Author(s):  

The aluminium-silicon (Al-Si) based on Metal Matrix Composites (MMCs) is widely used in lightweight constructions and transport applications requiring a combination of high strength and ductility. A grain refinement plays a crucial role in improving characteristics and properties of Al alloys. In this investigation, titanium diboride (TiB2) and scandium (Sc) inoculants were added to the Al-Si alloys for grain refinement of an alloy. In this investigation, the corrosion resistance rate of Al-Si cast alloy reinforced by TiB2 and Sc were measured by potentiostat (AUTOLAB) instrument. The aim of this research is to investigate the corrosion rate for Al-Si-TiB2-Sc composites that immersed in different concentration of acidic solutions. Besides, the immersion time of acidic solutions also was investigated. All the samples were prepared accordingly for ASTM standard by the composition of 6.0 wt% TiB2 and 0.6wt% Sc. All the samples undergo cold mounting technique for easy handling on corrosion tests. Then the samples were immersed in two different concentrations acidic medium solutions, which were 0.1.and 1.0 M hydrochloric acids (HCl). The corrosion rate also was investigated for immersion samples of 1.0 M HCl for 21 days. From the results obtained, added TiB2 and Sc onto Al-Si alloy gave the better properties in corrosion resistance. Corrosion rates to reduce when the samples were immersed in a lower concentration of acidic medium, 0.1 HCl. However, there are some significant on the result but it still following the corrosion rates trend. Thus, improvements to reinforcement content need to be done in further research to cover the lack of this corrosion rates trend.


Alloy Digest ◽  
1986 ◽  
Vol 35 (12) ◽  

Abstract UNS No. A03560 is a heat-treatable aluminum casting alloy. Normally it is used only when heat-treated (aged) strengths are required. It is recommended for high-strength, pressure-tight castings, intricate shapes and where good resistance to corrosion is needed. Its many applications include crank cases, gear cases, oil pans, airframe fittings and instrument housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-274. Producer or source: Various aluminum companies.


Alloy Digest ◽  
1988 ◽  
Vol 37 (3) ◽  

Abstract UNS NO. A96101 in the heat treated condition is used primarily for enclosed bus conductor where both high strength and high electrical conductivity are desirable. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-287. Producer or source: Various aluminum companies.


Alloy Digest ◽  
2020 ◽  
Vol 69 (11) ◽  

Abstract CarTech Ti-3Al-8V-6Cr-4Mo-4Zr, also known as Ti-3-8-6-4-4 and Beta C, is a metastable beta alloy used in the solution heat treated or solution heat treated and aged condition. It is appropriate for applications where very high strength, minimum weight, and corrosion resistance are important. Ti-3Al-8V-6Cr-4Mo-4Zr has gained in popularity among beta alloys because it is easier to melt and process, exhibiting low segregation, good workability, and good heat-treating properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-172. Producer or source: Carpenter Technology Corporation.


Alloy Digest ◽  
1963 ◽  
Vol 12 (8) ◽  

Abstract Cooper Alloy 22W is a high strength, heat resistant casting alloy with a low creep rate. It is recommended for heat applications where stress and hot gas corrosion rate are very high. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: SS-146. Producer or source: Cooper Alloy Corporation.


1970 ◽  
Vol 9 (9) ◽  
pp. 39-43
Author(s):  
Basu Ram Aryal ◽  
Jagadeesh Bhattarai

Simultaneous additions of tungsten, chromium and zirconium in the chromium- and zirconium-enriched sputter-deposited binary W-xCr and W-yZr are effective to improve the corrosion resistance property of the ternary amorphous W- xCr-yZr alloys after immersion for 240 h in 1 M NaOH solution open to air at 25°C. The corrosion rates of all the examined sputter-deposited (10-57)W-(18-42)Cr-(25-73)Zr alloys is higher than those of alloy-constituting elements (that is, tungsten, chromium and zirconium) in aggressive 1 M NaOH solution open to air at 25°C. The corrosion rates of all the examined sputter−deposited W–xCr–yZr alloys containing 10-57 at% tungsten, 18-42 at% chromium and 25-73 at% zirconium were in the range of 1.5-2.5 × 10−3 mm/y or lower which are more than two orders of magnitude lower than that of sputter-deposited tungsten and even about one order of magnitude lower than those of the sputter-deposited zirconium in 1 M NaOH solution. Keywords: Ternary W–Cr–Zr alloys; Amorphous; Corrosion rate; Open circuit potential; 1 M NaOH. DOI: http://dx.doi.org/10.3126/sw.v9i9.5516 SW 2011; 9(9): 39-43


2021 ◽  
Vol 1016 ◽  
pp. 592-597
Author(s):  
Masato Ikoma ◽  
Taiki Morishige ◽  
Tetsuo Kikuchi ◽  
Ryuichi Yoshida ◽  
Toshihide Takenaka

Mg alloys are very attractive materials for transportation industry due to their toughness and lightness. Recycling Mg alloys is desired for energy saving that otherwise would be required to produce its primary metal. However, secondary produced Mg tends to contain a few impurity elements that deteriorate its corrosion resistance. For example, contamination of Mg alloy by Cu induces second phase of Mg2Cu and it works as strong cathode, resulting in the corrosion rate rapidly increasing. It was previously reported that the corrosion resistance of Mg with impurity Cu was remarkably improved by addition of alloying element Zn. Addition of Zn into Mg formed MgZn2 phase and incorporated Cu into MgZn2 phase instead of Mg2Cu formation. In this way, since Zn serves to improve the corrosion resistance of Mg, Mg alloy with high Zn concentration may form a lot of MgZn2 and may have better corrosion resistance even with high Cu concentration. In this work, the corrosion behavior of Mg-6mass%-1mass%Al (ZA61) with different Cu content up to 1mass% was investigated. As a result, ZA61-1.0Cu had much lower corrosion rate compared to Mg-0.2%Cu and the corrosion rate was almost the same as that of pure Mg.


1970 ◽  
Vol 25 ◽  
pp. 53-61
Author(s):  
Minu Basnet ◽  
Jagadeesh Bhattarai

The corrosion behavior of the sputter-deposited nanocrystalline W-Cr alloys wasstudied in 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open to air usingimmersion tests and electrochemical measurements. Chromium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Cr alloys soas to show higher corrosion resistance than those of alloy-constituting elements in both 0.5M NaCl and 1 M NaOH solutions. In particular, the nanocrystalline W-Cr alloys containing25-91 at% chromium showed about one order of magnitude lower corrosion rates (that is,about 1-2 × 10-3 mm.y-1) than those of tungsten and chromium metals even for prolongedimmersion in 0.5 M NaCl solution at 25°C. On the other hand, the corrosion rate of thesputter-deposited W-Cr alloys containing 25-75 at % chromium was decreased significantlywith increasing chromium content and showed lowest corrosion rates (that is, 1.5-2.0 × 10-3 mm.y-1) after immersed for prolonged immersion in 1 M NaOH solution. The corrosion ratesof these nanocrystalline W-(25-75)Cr alloys are nearly two orders of magnitude lower thanthat of tungsten and more than one order of magnitude lower corrosion rate than that ofsputter-deposited chromium metal in 1 M NaOH solution. The corrosion-resistant of all theexamined sputter-deposited W-Cr alloys in 0.5 M NaCl solution is higher than in alkaline 1M NaOH solution at 25°C. Open circuit potentials of all the examined W-Cr alloys areshifted to more noble direction with increasing the chromium content in the alloys afterimmersion for 72 h in both 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air.Keywords: Sputter deposition, nanocrystalline W-Cr alloys, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI:  10.3126/jncs.v25i0.3300Journal of Nepal Chemical Society Volume 25, 2010 pp 53-61


2018 ◽  
Vol 65 (1) ◽  
pp. 79-86 ◽  
Author(s):  
V.V. Ravikumar ◽  
S. Kumaran

Purpose The purpose of this paper is to study the corrosion behaviour of Al-12Zn-3Mg-2.5Cu alloy by cast, precipitation hardening and non-isothermal step rolling cum cold/cryo rolling (−80 and −196°C) in 3.5 per cent NaCl solution. Design/methodology/approach Aluminium alloy with high alloying concentration (Zn: 12 per cent, Mg: 3 per cent, Cu: 2.5 per cent) was prepared by squeeze casting method with controlled process parameters. The cast alloy was solution treated at 450°C for 24 h and aged at 120°C with varying time intervals. Initially, the alloy also underwent non-isothermal step rolling from 6 mm to 3 mm at 400-100°C at the step of 100ºC with 15% reduction in thickness. Non-isothermal rolled alloy (3 mm thickness) was the starting material for further rolling at three different temperatures, such as room temperature, −80 and −190°C with 85 per cent reduction. Microstructural evolution during precipitation and thermo-mechanical processing was studied with the help of optical microscopy and electron microscopy. A potentio-dynamic polarization study was performed to evaluate the corrosion behaviour of Al-12Zn-3Mg-2.5Cu alloy processed in different conditions in 3.5 per cent NaCl solution. Findings There is a distinct evidence that the alloy exhibits varying corrosion resistance by changing its structural features. In fact, the alloy with ultra-fine grained structure exhibits good corrosion resistance than that of alloy in cast. This is attributed to a greater grain boundary region with high dislocation density, and plastic strain adversely affects the corrosion resistance. Originality/value The results obtained by this investigation help in understanding the effect of precipitation hardening and non-isothermal step rolling cum cold/cryo rolling (−80 and −196°C) on corrosion behaviour.


Author(s):  
Venkata Siva Teja Putti ◽  
S Manikandan ◽  
Kiran Kumar Ayyagari

Abstract Titanium (Ti-6Al-4V) is an α+β phase-field alloy utilized in many industries due to its high strength-to-weight ratio and near-net shaping capability. Solution treated & aging, and stress relief annealing processes were performed on the samples to increase the strength and % of elongation. The heat-treated samples then thermally cycled for 500 cycles, 1000 cycles, and 1500 cycles to evaluate the microhardness and tensile properties. The presence of martensite and α2 precipitates in the thermally cycled samples was confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). In this investigation, at 1000 thermal cycles, all specimens show improvement in both hardness and strength when compared within the cycles. Solution-treated and aging (STA), stress relief annealing (SRA), and without any heat-treatment (WHT) processes have their highest hardness values recorded for 1000 thermal cycles, and the values are 471 HV0.5, 381 HV0.5, and 374.6HV0.5, respectively. For the SRA process, ultimate tensile strength (UTS) of 925 MPa and yield strength (YS) of 896 MPa have resulted in 1000 cycles. Similarly, at 1000 thermal cycle WHT processed samples yielded UTS of 920 MPa and YS of 885 MPa. STA process samples that are heat-treated for 1000 thermal cycles have better strength properties than SRA and WHT and had a UTS of 1530MPa and YS of 1420MPa. From a ductility point of view, a maximum elongation of 29% for the STA process has resulted. Compared to forged titanium alloy (base metal), an increase of 31% elongation and 41% ultimate tensile strength for solution treated and aging process at 1000 cycles has resulted in this investigation.


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