Influence of Titanium Additions on the Corrosion Behavior of Cu-Al-Ni Shape Memory Alloys

2021 ◽  
Vol 1021 ◽  
pp. 55-67
Author(s):  
Nawal Mohammed Dawood ◽  
Abdul Raheem Kadhim Abidali

The Cu- Al-Ni shape memory alloys have numerous industrial applications such as actuators, Cryofit hydraulic couplings, fire safety valves ,etc. while the parts that soaked in the sea water suffer severe corrosion that lead to worsening in the properties of the alloys. In the current research, the effect of adding titanium on corrosion behavior of the shape memory alloys (Cu-13wt. %Al-4wt. %Ni) were studied. Titanium was added in different weight ratios (0.4, 0.8, and 1.2 wt.%) to the base alloy. The alloys were prepared using powder metallurgy, whereby the alloys were sintered with two stages of heating under Argon atmosphere, at 550°C for (120 min.) and 950°C for (180 min.)respectively. All the sintered samples are solution treated by heating the samples at 900 °C for (60 min.) followed by rapid quenching in ice water at ( 3 ~ 6) °C. After that aging heat treatment has been done for quenched samples at 200 °C for (30 hrs.) followed by rapid quenching in iced water. Several tests such as microstructures observation and phase analysis using scanning electron microscope, energy dispersive spectrometer, and X-ray diffraction analysis have been done. Further , Corrosion behavior for all samples in aged conditions in 3.5%NaCl solution have been performed. Corrosion test results have showed that the highest corrosion resistance was found in the addition of (1.2 wt.% Ti) which give the lowest corrosion rate (0.003 mpy) in 3.5% NaCl solution . Noted that the corrosion rate of base alloy was (9.021)mpy. EDS analysis showed chemical composition of the aged surface and also mapping images for the distribution of Cu, Al, Ni, and Ti elements on the surface. Phases formed on aged samples conditions are α-Cu and AlCu3.

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
L. A. Falcon ◽  
E. Bedolla B. ◽  
J. Lemus ◽  
C. Leon ◽  
I. Rosales ◽  
...  

The corrosion behavior of TiC particles reinforced Mg-Al alloy in 3.5% NaCl solution has been evaluated using electrochemical techniques. Tested alloys included an Mg-9Al (Mg AZ91E) alloy with and without 56 wt. % TiC particles. Electrochemical techniques included potentiodynamic polarization curves, linear polarization resistance, electrochemical noise, and electrochemical impedance spectroscopy measurements. All techniques showed that the composite exhibited a lower corrosion rate than the base alloy. Evidence of galvanic effects that increased the composite corrosion rate was found between the matrix and the TiC particles. Additionally, the tendency to suffer from pitting corrosion was higher for the base alloy than that for the composite. Electrochemical impedance results showed the importance of adsorption/diffusion phenomena in both materials.


2011 ◽  
Vol 56 (18) ◽  
pp. 6389-6396 ◽  
Author(s):  
X.T. Sun ◽  
Z.X. Kang ◽  
X.L. Zhang ◽  
H.J. Jiang ◽  
R.F. Guan ◽  
...  

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


2009 ◽  
Vol 620-622 ◽  
pp. 153-156 ◽  
Author(s):  
Kyung Chul Park ◽  
Byung Ho Kim ◽  
Jong Jin Jeon ◽  
Yong Ho Park ◽  
Ik Min Park

In the present work, the effect of Sn addition on the corrosion behavior of Mg–5Al–1Zn alloys was investigated. Microstructure, potentiodynamic polarization and immersion tests were carried out in 3.5% NaCl solution of pH 7.2 to estimate the corrosion behavior of AZ51 alloys with and without Sn addition. Mg17Al12 and Mg2Sn phases were mainly precipitated in inter-dendrite structures. With increasing the Sn content, the volume fraction of the Mg2Sn phase was increased and coarsening tendency was observed. The corrosion resistance was increased by Sn addition. Especially, the AZ51-5wt.%Sn alloy characterized the superior corrosion resistance among the four alloys. The Sn is known for a high hydrogen overvoltage and the secondary phases effectively formed the network structure, resulting in a drastically decreasing corrosion rate of AZ51 alloy.


2020 ◽  
pp. 2000865 ◽  
Author(s):  
Johanna-Maria Frenck ◽  
Malte Vollmer ◽  
Marcel Mandel ◽  
Lutz Krüger ◽  
Thomas Niendorf

Author(s):  
Ranjit Singh ◽  
Ravi Pratap Singh ◽  
Rajeev Trehan

Shape memory alloys (SMAs) have been well known for their superior and excellent properties which makes them an eligible candidate of paramount importance in real-life industrial applications such as; orthopedic implants, actuators, micro tools, stents, coupling and sealing elements, aerospace components, defense instruments, manufacturing elements, bio-medical appliances, etc. In spite of their exceptional properties, the effective processing of these alloys is always seen as a challenge by researchers around the globe. The present article has been therefore attempted to explore the numerous studies conducted to process these alloys by employing the principles of electrical discharge machining (EDM) and its allied approaches. The NiTi-based SMAs have been revealed to be explored majorly among the several types SMAs. The several investigations carried out in the domain of EDM, Wire-EDM, and some conventional processing of various types of SMAs have also been critically reviewed and reported. It also highlights the numerous experimental, theoretical, modeling, and optimization-based researches attempted in EDM of SMAs. It was also reported that the proper selection of process variables, tool electrode, and the dielectrics can substantially improve the overall process effectiveness. Among the various accessible EDM variants used for the processing of SMAs, attempted by the umpteen investigators, the wire-cut EDM process has been revealed as the most explored one for cutting SMAs than the other allied processes such as: die-sinking EDM and powder-mixed EDM. The micro-machining applications of EDM have also been deliberated briefly. The last section of the article reports about the opportunities and the challenges for future research.


2015 ◽  
Vol 1120-1121 ◽  
pp. 773-778
Author(s):  
Zhen Guang Liu ◽  
Xiu Hua Gao ◽  
Lin Xiu Du ◽  
Jian Ping Li ◽  
Ping Ju Hao

The corrosion behavior of pipeline steel containing 1%Cr is studied by using immersion experiment. The corrosion rust is characteried with macroscopic/microscopic surface morphology, corrosion kinetics and corrosion phases. The results demonstrate that the main corrosion products are lepidocrocite and goethite, Cr-rich compound consists of the inner layer. The corrosion process could be divided into three stages. At stage 1, the corrosion rate decreases fast, and the distributed corrosion products are formed. At stage 2, the granular corrosion products appear on coupons surface gradually, and a plain corrosion rate is obtained. At stage 3, a compact and dense corrosion layer attaches to coupons surface, and corrosion rate decreases mildly.


Sign in / Sign up

Export Citation Format

Share Document