Al-TM合金中準(zhǔn)晶近似相的結(jié)構(gòu)研究.pdf

1、大連理工大學(xué)博士學(xué)位論文AlTM合金中準(zhǔn)晶近似相的結(jié)構(gòu)研究姓名：莫志民申請(qǐng)學(xué)位級(jí)別：博士專業(yè)：金屬材料指導(dǎo)教師：郭可信1999.6.1AbstractAstructuralmodelofthemonoclinicA1，Cophasewasderivedbyre。arrangingthesub—unitofthemonoclinicA113C04phase，whosestructurewassolvedbysinglecrystalX—r

2、aydiffractionThesimulatedhighresolutionimageandelectrondiffractionpatternagreewellwiththeexperimentalonesBasedonthismodel，thepowderXraydiffractogramwasreindexedandastructuralmodeloftheorthorhombicAl，CowasdeducedHighresol

3、utionmicroscopicstudyonthenew—foundhexagonalVAlCrFephase(a24069A，C=12546A，P6／m)withgiantunitcellrevealedthecloserelationshipamongV九一A1dMnandKAlCrNiphasesBasedontheseresults，astructuralmodeloftheVphasewasderivedandmodifie

4、dbyintroducingofthesubunitoftheEA1dCrphasewhichiSalsoanapproximantWealsotriedtosolvethestructureoftheVphasebyelectroncrystallographyand3DreconstructionApropermethodwasdevelopedforCTFcorrectionofapproximantstructureHighre

5、solutionimagestakenalong11directionswereprocessedandamplitudesandphasesofsomestrongreflectionswerederivedA3DpotentialmapwasobtainedbyinverseFFTandthestructuralmodelwasmodifiedfurtherAtlastasinglecrystaloftheV—A1CrFephase

6、wasfoundandthestructurewasdeterminedbythecombinationofdirectmethodsandhighresolutionelectronmicroscopyThestructurecontainsalargequantityofslightlydistortedicosahedraandtheconnectionamongthemwasanalyzedKeywords：crystallin