Whilst working in private military-industrial laboratory (Center for Scientific-Technical Research) in
Neubabelsberg in 1901, Wilm discovered
age hardening, in particular age hardening of aluminium alloys. This discovery was made after
hardness measurements on
Al-Cu alloy specimens were serendipitously found to increase in hardness at room temperature. This increase in hardness was identified after his measurements were interrupted by a weekend, and when they were resumed on the Monday the hardness had increased. By 1906, Wilm had developed an alloy – Al-(3.5–5.5%)Cu-Mg-Mn (Mg and Mn were < 1%), for which a patent was filed. Later this patent was purchased and the alloy marketed as
Duralumin. Somewhat unusually, Wilm did not write his first article on age hardening until 1911. == Death ==