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Modeling and parametric optimization of friction stir welding of aluminium alloy AA7068-T6 using response surface methodology and desirability function analysis

Bindu M. D., Tide P. S., Bhasi A. B., Ramachandran K. K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 4

art. no. e137936

EN

In this investigation, high specific strength precipitation hardenable alloy AA7068-T6 was joined using friction stir welding. Experiments were carried out using the three factor-three level central composite face-centered design of response surface methodology. Regression models were developed to assess the influence of tool rotational speed, welding speed, and axial force on ultimate tensile strength and elongation of the fabricated joints. The validity of the developed models was tested using the analysis of variance (ANOVA), actual and adjusted values of the regression coefficients, and experimental trials. The analysis of the developed models together with microstructural studies of typical cases showed that the tool rotational speed and welding speed have a significant interaction effect on the tensile strength and elongation of the joints. However, the axial force has a relatively low interaction effect with tool rotational speed and welding speed on the strength and elongation of the joints. The process variables were optimized using the desirability function analysis. The optimized values of joint tensile strength and elongation – 516 MPa and 21.57%, respectively were obtained at a tool rotational speed of 1218 rpm, welding speed of 47 mm/ min, and an axial force of 5.3 kN.

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Influence of tool traverse speed on the characteristics of dissimilar friction stir welded aluminium alloy, AA5052 and HSLA steel joints

Ramachandran K. K., Murugan N., Shashi Kumar S.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 4

822--830

EN

In the present work 3 mm thick aluminium alloy AA5052 and HSLA steel were successfully butt joined using friction stir welding (FSW) technique. The FSW trials were carried out by varying the tool traverse speed while keeping the other parameters constant. The joint characteristics such as ultimate tensile strength (UTS), microhardness, microstructure at the joint interface and fracture surface of fractured tensile specimens were investigated. SEM and EDS analysis suggest that in all cases intermetallic compound (IMC) layer is formed at the joint interface and its thickness is critical in the tensile strength of the joint. For a given tool rotational speed, axial load and tool tilt angle, the tool traverse speed has significant influence on the thickness of IMC layer formed and hence on the joint strength. The highest joint strength of about 91% of UTS of the base aluminium alloy is obtained at tool traverse speed of 45 mm/min and the UTS follow approximately a centre peak type variation against tool traverse speed.

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Sequential extractive separation of platinum(IV) and palladium(II) from iodide media with mesityl oxide

Pillai A. R., Ramachandran K. K., Rao T.P.

Chemia Analityczna

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1998

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Vol. 43, No. 1

41-46

EN

Liquid-liquid extractive separation of platinum(IV) and palladium(II) has been investigated as a function of iodide concentration with mesityl oxide as extractant. The separation consists of one step of extraction with mesityl oxide from an aqueous phase maintained at pH 4 and KI concentration in the range 10(-7)-10(-6) mol l(-l), 3 three step scrubbing with an aqueous phase maintained at pH 4 and 10(-6) mol 1(-1) in KI and one step of stripping with 10 ml of water after addition of 40 ml of toluene to messily oxide phase. The liquid-liquid extraction behaviour of other noble and base metals has been studied: The above developed separation procedure is highly selective as seen from recovery of platinum(IV) and palladium(II) from complex mixtures consisting of other noble and base metals.

PL

Badano rozdzielanie i spektrofotometryczne oznaczanie platyny(IV) i palladu(II) przy zastosowaniu dwukrotnej ekstrakcji tlenkiem mezytylu. Faza wodna powinna być kwaśna (pH 4) i zawierać KI w stężeniu 10(-7)-10(-6) mol 1(-1) przy pierwszej ekstrakcji oraz 10z mol 1 przy drugiej ekstrakcji. Stwierdzono, że pozostałe metale szlachetne i szereg innych metali nie przeszkadzają w oznaczaniu.