COMPARISON OF THE CORROSION RESISTANCE OF 61S AND AW10 ALLOYS, AND THE INFLUENCE OF ADDITION OF COPPER OR ZINC UP TO 0.5% EACH ON THEM
1953 Volume 1953 Issue 7 Pages 44-50
Details
1953 Volume 1953 Issue 7 Pages 44-50
Comparison of the corrosion resistance of 61S and AW10 alloy which are used as the heat-treatable Al alloys for marine service in America and England respectivly, and the influence of addition of Cu or Zn up to about 0.5% each on them were examined. The The tensile tests on the 1mm thick specimens which were heat-treated to "O" "T4" "T6" conditions were done befor and after the corrosion tests namely, accelerated corrosion method, immersion in polluted sea-water, or stress corrosion. Results obtained are as follows,
(i) The difference of the performance of 61S and AW10 alloys are so small that we can not determine which is superior than another.
(ii) Corrosion resistance of these alloys are decreased with copper content, and the degree of deteriorous effect of copper on AW10 is greater than on 61S.
(iii) On the effects of zinc, we can say, they are negrigibly small
(iv) The effect of Cr(0.25%) in 61S and Mn(0.7%) in AW10 are very similar, both in crease the tensile strength and improve the resistivity against stress corrosion of "T6" condition.
By such results, the present author believes that it may be allowed to increase to some degree of the upper limits of Cu and Zn in the Lloyds specification and may be desirous to set the lower limit of Mn content in that.
