Searching about microstructure of Cu-Ni-Zn alloys I came across an article (published 2017) which in Conclusion says:

Blockquote It was observed that the starting and finishing transformation temperatures from austenite to martensite (A_s, A_f) affected by Zn percent. Blockquote

As far as know, the starting and finishing temperatures from austenite to martensite must be M_s and M_f, so I'm confused now. Any ideas if it's a mistake in the article or everything is Ok and I'm getting this wrong?


I think you are mixing apples and oranges , or bronze and steel. Aluminum and manganese bronzes both have a "martensite" transformation that modestly hardens them. The reference must be to manganese bronze because aluminum bronze has no intentional zinc. Manganese bronze is primarily copper and zinc with less amounts of Al. Mn, Fe and some grades contain Ni. I do not recall the crystal structure of the bronzes before the transformation. Addenda: One can find references to heat-treating aluminum bronze ( eg. 9D , C95500) but it contains no zinc. I do not find references to heat-treatment of manganese bronze . I believe that is because the increase in strength is too small to be worthwhile. But as a lone voice on the net, I say there is a (small) martensite reaction in manganese bronze.

  • $\begingroup$ It has nothing to do with the composition of alloys. Generally: A_s: is Austenite start temperature A_f: Austenite finish temperature M_s: Martensite start temperature M_f: Martensite finish temperature $\endgroup$
    – Negarin
    Sep 3 '21 at 19:19
  • $\begingroup$ Because it is not a ferrous system they may they are not be using ferrous terminology . So maybe : A s = alpha phase starts transforming, and A f = alpha finishes transforming. $\endgroup$ Sep 6 '21 at 18:48

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