Effects of Cooling Rate on Morphology, Microhardness and Volume Fraction of Mg-Zn-Y Quasicrystals
Mg72.5Zn26Y1.5 (at.%) quasicrystal alloys were investigated under different solidification conditions. The cooling curves were gathered by the multi-channel temperature acquiring system and the corresponding microstructures were analyzed. The morphology, microhardness and volume fraction of quasicrystals were detailedly studied. The effects of cooling rate on the above three aspects were also studied and the relation schema among them were exhibited. The results show that the quasicrystal size tend to smaller, its microhardness and volume fraction gradually increased, and the quasicrystal morphology changed from bulk polygon to petal-like and finally changed to plat X-shape with the elevated cooling rate from 2.3K/s to 181.2K/s. However, the quasicrystal nucleation will be restrained and amorphous matter will be created if the cooling rate exceed the critical point which make against the formation of quasicrystals with high performance.
Guojun Zhang and Jessica Xu
Z. F. Wang et al., "Effects of Cooling Rate on Morphology, Microhardness and Volume Fraction of Mg-Zn-Y Quasicrystals", Advanced Materials Research, Vols. 160-162, pp. 470-474, 2011