AbstractThe microstructure and the thermal stability of rapid solidified centrifugally atomised AI–3Cr–X (X=1Ni, 3Ni, 0·3Mo, 1Si, or 3Si, at.-%) powders were studied. Three main types of microstructure were observed in the powders: cellular, globular, and rosettelike. Some powders exhibited a mixture of these. In the atomised state the alloys usually had two phases, intermetallic Al13Cr2andα-Al solid solution. Thermal stability was studied for a range of temperatures from 20 to 500°C. The phase Al3Ni appeared in the nickel containing alloys and grew upon heat treatment. The molybdenum containing alloy did not show any noticeable change upon heat treatment. With respect to the silicon containing alloys, the intermetallic Al13Cr2transformed into Al13Cr4Si4at high temperatures. On the basis of bibliographic information a nucleation map was calculated relating the prevalence of the intermetallic Al13Cr2phase and theα-Al phase to the particle diameter and the chromium concentration of powder obtained by centrifugal atomisation.MST/3273