Comparative Evaluation of Corrosion Behavior of Friction Stir Welded AZ61A Magnesium Alloy Weldments in Immersion Corrosion Tests and Salt Spray Corrosion Tests Using Response Surface Methodology

2012 ◽  
Vol 65 (3) ◽  
pp. 275-287
Author(s):  
A. Dhanapal ◽  
S. Rajendra Boopathy ◽  
V. Balasubramanian
2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ashok Kumar M ◽  
Thirumalaikumarasamy D ◽  
Paventhan R ◽  
Thirumal P

An investigation was carried out to quantify and characterize the corrosion behaviour of AZ31B magnesium alloy joints. Extruded Mg alloy plates of 6 mm thick of AZ31B grade were butt welded using a solid state, environmentally cleaner welding process, friction stir welding process. The weld specimens were underwent immersion, salt spray, pitting and galvanic corrosion tests in order to quantify and characterize the corrosion rates of the welds with the influence of different pH values, chloride ion concentration and the corrosion time. The corrosion rates, microstructure, scanning electron microscopy and X-ray diffraction analysis concludes the optimum parameter for the usage of the magnesium alloy welds for the best service applications. Keywords: Keywords: EDM, Alumina and Genetic Algorithm


2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
A. Dhanapal ◽  
S. Rajendra Boopathy ◽  
V. Balasubramanian ◽  
K. Chidambaram ◽  
A. R. Thoheer Zaman

Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using advanced welding process and friction stir welding (FSW) processes. The specimens were exposed to salt spray conditions and immersion conditions to characterize their corrosion rates on the effect of pH value, chloride ion concentration, and corrosion time. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of FSW welds in salt spray corrosion test and galvanic corrosion test using design of experiments. The corrosion morphology and the pit morphology were analyzed by optical microscopy, and the corrosion products were examined using scanning electron microscope and X-ray diffraction analysis. From this research work, it is found that, in both corrosion tests, the corrosion rate decreases with the increase in pH value, the decrease in chloride ion concentration, and a higher corrosion time. The results show the usage of the magnesium alloy for best environments and suitable applications from the aforementioned conditions. Also, it is found that AZ61A magnesium alloy welds possess low-corrosion rate and higher-corrosion resistance in the galvanic corrosion test than in the salt spray corrosion test.


2021 ◽  
Vol 63 (2) ◽  
pp. 151-156
Author(s):  
Lihua Gong ◽  
Weimin Guo ◽  
Feng Pan

Abstract The influence of metal inert-gas arc welding (MIG) on the corrosion behavior of 6061-T6 aluminum alloy in a simulated tropical marine atmospheric environment (related to high temperature, high humidity and high salt spray) were examined by dry-wet alternate immersion corrosion tests. The equivalent conversion was used to design the accelerated test time. The results show that in the initial stage, the intermetallic compound, rich in Fe, Si and Cu, had little influence on corrosion resistance in the heat-affected zone. For a corrosion time of 3 days in a tropical marine atmospheric environment, the corrosion rate of the welded joint increased rapidly, even reaching 3.5 times that of the base metal. Though the corrosion products had significant impact on slowing down the corrosion rate, as with the base metal, the corrosion rate of the welded joint was nearly double that of the base metal during the longest cycle period involving alternate immersion corrosion tests for 20 days.


2017 ◽  
Vol 13 (3) ◽  
pp. 377-390 ◽  
Author(s):  
Ahmed Naser ◽  
Basil Darras

Purpose The purpose of this paper is to present a model to predict the micro-hardness of friction stir processed (FSPed) AZ31B magnesium alloy using response surface methodology (RSM). Another objective is to identify process parameters and through-thickness position which will give higher micro-hardness values. Moreover, the study aims at defining the factor that exhibits the most effect on the micro-hardness. Friction stir processing (FSP) machine can then be fed with the optimized parameters to achieve desirable properties. Design/methodology/approach An experimental setup was designed to conduct FSP. Several AZ31B magnesium samples were FSPed at different combinations of rotational and translational speeds. The micro-hardness of all the combinations of process parameters was measured at different through-thickness positions. This was followed by an investigation of the three factors on the resulting micro-hardness. RSM was then used to develop a model with three factors and three levels to predict the micro-hardness of FSPed AZ31 magnesium alloy within the covered range. The analyses of variance in addition to experimental verification were both used to validate the model. This was followed by an optimization of the response. Findings The model showed excellent capability of predicting the micro-hardness values as well as the optimum values of the three factors that would result in better micro-hardness. The model was able to capture the effects of rotational speed, translational speed, and through-thickness position. Results suggest that micro-hardness values were mostly sensitive to changes in tool rotational speed. Originality/value FSP is considered to be one of the advanced microstructural modification techniques which is capable of enhancing the mechanical properties of light-weight alloys. However, the lack of accurate models which are capable of predicting the resulted properties from process parameters hinders the widespread utilization of this technique. At the same time, RSM is considered as a vital branch of experimental design due to its ability to develop new processes and optimize their performance. Hence, the developed model is very beneficial and is meant to save time and experimental effort toward effective use of FSP to get the desired/optimum micro-hardness distribution.


2014 ◽  
Vol 789 ◽  
pp. 622-626
Author(s):  
Peng Chao Zhang ◽  
Jian Zhang ◽  
Jin Chuan Jie ◽  
Yuan Gao ◽  
Yong Dong ◽  
...  

The effect of different alloying elements on corrosion behavior of copper alloys was investigated using electrochemical corrosion and salt spray corrosion test in NaCl solution. Cu-Ag has the most stable corrosion current in the potentiostatic scanning test, exhibiting a better corrosion resistant performance. It can be analyzed from corrosion surface morphologies that Cu-Ag presents exfoliation corrosion mechanism while Cu-Sn shows crevice corrosion mechanism. Cu-Mg has a complex corrosion process caused by multiple corrosion mechanism. In the salt spray corrosion test, the corrosion degree of Cu-Ag is lighter than those of Cu-Sn and Cu-Mg after 24h test. Therefore, the Cu-Ag alloy exhibits the best corrosion resistance in chloride solution.


Author(s):  
Ravi Butola ◽  
Ranganath M. Singari ◽  
Qasim Murtaza ◽  
Lakshay Tyagi

In the present work, nanoboron carbide is integrated in the aluminum matrix using friction stir processing: by varying process parameters, that is, tool pin profile, tool rotational speed and tool traverse speed, based on Taguchi L16 design of experiment. A self-assembled monolayer is successfully developed on the substrate to homogeneously and uniformly distribute the reinforcement particles. Response surface methodology and artificial neural network models are developed using ultimate tensile strength and total elongation as responses. Percentage absolute error between the experimental and predicted values of ultimate tensile strength and total elongation for the response surface methodology model is 3.537 and 2.865, respectively, and for artificial neural network is 2.788 and 2.578, respectively. For both the developed models experimental and forecasted values are in close approximation. The artificial neural network model showed slightly better predictive capacity compared to the response surface methodology model. From the scanning electron microscopy micrograph, it is evident that throughout the matrix B4C reinforcement particles are well distributed also; with increasing tool rotational speed grain size decreases up to 1200 r/min; on further increasing the tool rotational speed particles starts clustering.


Sign in / Sign up

Export Citation Format

Share Document