Secondary Phases Present in Spray Formed Al-10.5Zn-2.0Mg-1.5Cu Alloy
Al-10.5Zn-2.0Mg-1.5Cu alloy was produced by spray forming (SF) technique. The initial microstructure, particularly secondary phases, present in the as-SFed alloy was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with attached energy dispersive X-ray spectroscopy (EDS). The results indicated that the equiaxed α-Al grains have an average size of about 18-20 μm in diameter. The intergranular phase was identified as MgZn2 by selected area electron diffraction (SAED) pattern, which was also distributed in the grain interior as well as Al2Mg3Zn3. A needle-like Al23Cu(FeCrMn)4 precipitate was detected. The combined analysis of morphology and crystallographic structure suggested that the Al23Cu(FeCrMn)4 grew along its long axis of <001> orientation. The refinement of the intergranular phases occurred, which is probably due to a decreased amount of eutectic liquid phase finally solidifying on a large area of grain boundaries.
Zhengyi Jiang and Chunliang Zhang
S. Guo et al., "Secondary Phases Present in Spray Formed Al-10.5Zn-2.0Mg-1.5Cu Alloy ", Advanced Materials Research, Vols. 97-101, pp. 1073-1076, 2010