Y.H.Zhu
材料科学技术（英文）
Furnace cooling is a slow cooling process. It is of importance to study structural evolution and its effects on the properties of alloys during the furnace cooling. Decomposition of aluminium rich α phase in a furnace cooled eutectoid Zn-Al based alloy was studied by transmission electron microscopy. Two kinds of precipitates in the α phase were detected in the FCZA22 alloy during ageing at 170℃. One was the hcp transitional α′m phase which appears as directional rods and the round precipitates. The other was the fcc α′′m phase. It was found that the transitional phaseα′m grew in three preferential directions of <110>, <011> and <101>. The orientation relationship between the α phase and transitional phase α′m was determined as , . The non-equilibrium phase decomposition of the α phase is discussed in correlation with the equilibrium phase relationships. (02-2) 'm (fcc)// (02-2) (fcc) , [-111] 'm (fcc)// [-233] (fcc).
The non-equilibrium phase decomposition of the phase is discussed in correlation with the equilibrium phase relationships.
关键词:
Phase decomposition
,
decomposition
,
microstructural
,
evo
Y.H.Zhu
,
W.B.Lee
,
S.To
材料科学技术（英文）
The nanostructural evolution and phase transformation of the films of a Zn-Al based alloy (Zn¬68Al¬10Cu¬22 in wt pct) have been studied by using X-ray diffraction and scanning electron microscopy. Nanostructural thin films of the Zn-Al based alloy were produced by using an electron beam deposition technique. It was found that a nanocrystalline phase ηn' had a strong preferred crystal orientation at (0002) crystal planes in the as-deposited films. During ageing at 220℃, the decomposition of nanophase ηn' started with clustering to form Z-zones, and transitional phase, which was accompanied by an eutectoid decomposition of the ηn' phase: ηn' →βeut'+T'. Decomposition, such as clustering and the formation of the Z-zones, and the transitional phase etc. were observed in the nanophaseβeut'. The formation and the decomposition of the transitional phase of micrometers in size were involved in the decomposition of the main nanophase ηn'. The mechanism of the Z-zones formation and the stability of nanophases were discussed.
关键词:
Ageing
,
null
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null
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