کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1601444 | 1005198 | 2008 | 6 صفحه PDF | دانلود رایگان |
An arc-melted Zr73.5Nb9Cu7Ni1Al9.5 alloy consists of dendritic body-centered cubic solid solution and a mixture of ultrafine body-centered tetragonal Zr2Cu-type and hexagonal close-packed MgZn2-type phases in the ultrafine matrix. This composite exhibits two exothermic reactions upon heating to 973 K with a heating rate of 40 K/min. After the first exothermic reaction nano-scale ω-phase particles have formed in the β-phase dendrites indicating a decomposition of the supersaturated solid solution upon heating. At the early stage during the decomposition of the β-phase the ω-phase is coherent with the parent phase without clear structural differences. However, semicoherency between the β- and the nano-scale ω-phase regions was observed during the growth of the ω-phase. This structural semicoherency causes nano-scale twinning in the β-phase dendrites around the ordered ω-phase in order to release the mismatch energy at the interfaces between the ordered ω- and β-phases.
Journal: Intermetallics - Volume 16, Issue 4, April 2008, Pages 538–543