INFLUENCE OF A LOW TEMPERATURE AGEING ON THE PROPERTIES OF AL-6.5%SI-0.35%MG ALLOY

OB Umaru; M Abdulwahab; NM Hafsat; H Maidawa; AO Murtada; TM Suleiman

doi:10.4314/njt.353.1132

INFLUENCE OF A LOW TEMPERATURE AGEING ON THE PROPERTIES OF AL-6.5%SI-0.35%MG ALLOY

Authors

OB Umaru DEPT. OF MECHANICAL/PRODUCTION ENG’G, ABUBAKAR TAFAWA BALEWA UNIV. BAUCHI, BAUCHI STATE, NIGERIA
M Abdulwahab DEPARTMENT OF METALLURGICAL AND MATERIALS ENGR., AHMADU BELLO UNIV., ZARIA, KADUNA STATE, NIGERIA
NM Hafsat DEPT. OF MECHANICAL/PRODUCTION ENG’G, ABUBAKAR TAFAWA BALEWA UNIV. BAUCHI, BAUCHI STATE, NIGERIA
H Maidawa DEPT. OF MECHANICAL/PRODUCTION ENG’G, ABUBAKAR TAFAWA BALEWA UNIV. BAUCHI, BAUCHI STATE, NIGERIA
AO Murtada DEPT. OF MECHANICAL/PRODUCTION ENG’G, ABUBAKAR TAFAWA BALEWA UNIV. BAUCHI, BAUCHI STATE, NIGERIA
TM Suleiman DEPT. OF MECHANICAL/PRODUCTION ENG’G, ABUBAKAR TAFAWA BALEWA UNIV. BAUCHI, BAUCHI STATE, NIGERIA

DOI:

https://doi.org/10.4314/njt.353.1132

Keywords:

low temperature aging, aluminum alloys, corrosion resistance, one-step ageing, elemental sodium

Abstract

The effect of a low temperature ageing treatment on the hardness, tensile and corrosion characteristics of sand cast Al-6.5%Si-0.35%Mg alloy was studied. The temper conditions are low temperature ageing at 90^oC, 95^oC, 100^oCand 105^oC respectively followed by ageing to 180^oC for 2 hrs. This was compared with the control sample which was aged directly to 180^oC for 2hrs. The hardness of the Al-6.5%Si-0.35%Mg alloy was measured using the Rockwell-HRB scale hardness tester, while the tensile characteristic was evaluated using a graphical tensometer. The corrosion resistance of the alloy was evaluated using weight loss analysis in simulated sea water environment. An increase in the hardness characteristic was observed in the low temperature ageing at 90^oC (7.8 HRB) as compared with (6.0 HRB) that was obtained for the control. From the tensile results obtained, the extension value for the control samples was (1.4 mm) while the sample with a low temperature ageing of 105^oC gave the highest extension of (2.26 mm). Remarkable decrease in corrosion rate was observed at 95^oC (2.3373 mm/yr x10^-7) as compared with the control of (5.2049 mm/yr x10^-7). From the Optical Microscope (OPM) and Scanning electron microscope (SEM) results, it was observed that the microstructures were refined for low temperature ageing when compared with the control samples. From these results, it can be deduced that the low temperature ageing treatment had an appreciable influence on the properties of this alloy.

http://dx.doi.org/10.4314/njt.v35i3.12

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Issue

Vol. 35 No. 3 (2016)

Section

Chemical, Industrial, Materials, Mechanical, Metallurgical, Petroleum & Production Engineering

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How to Cite

INFLUENCE OF A LOW TEMPERATURE AGEING ON THE PROPERTIES OF AL-6.5%SI-0.35%MG ALLOY. (2016). Nigerian Journal of Technology, 35(3), 550-554. https://doi.org/10.4314/njt.353.1132