The main features of martensite transformation in melt-quenched Fe-31.4% Ni alloy on cooling below room temperature have been studied. It is found that the ribbon 50～60 μm thick, prepared by spinning technique, is a...The main features of martensite transformation in melt-quenched Fe-31.4% Ni alloy on cooling below room temperature have been studied. It is found that the ribbon 50～60 μm thick, prepared by spinning technique, is a natural composite in which isothermal and surface martensite are not formed, while athermal martensite forms at lower temperature, all factors being the same, as compared to the alloy of the same composition and grain size, prepared by recrystallization.展开更多
Surface morphology, physical-chemical properties of skeletal iron catalysts prepared by leaching of the rapidly quenched(RQ) and naturally quenched(NQ) Fe-Al alloys with an aqueous solution of NaOH were characterized...Surface morphology, physical-chemical properties of skeletal iron catalysts prepared by leaching of the rapidly quenched(RQ) and naturally quenched(NQ) Fe-Al alloys with an aqueous solution of NaOH were characterized by using a series of techniques including XRD, BET, XPS, SEM, H_2 and CO-TPD. It was found that the RQ skeletal iron catalyst exhibits a smaller particle size, larger specific surface area and pore volume than the NQ one. The H_2 and CO-TPD experiments showed that the RQ skeletal iron exhibits stronger affinity for H_2 and milder affinity for CO compared with the NQ one. But the NQ skeletal catalyst shows a better thermal stability than the RQ catalyst.展开更多
The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid...The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid solidification refines the grain size. extends the solid solubility of Si in Al and Introduces a high density ot defects which exist in the forms of vacancies, dislocations and dislocation loops. etc.. The decomposition process of the alloys was fol lowed by using differential scanning calorimeter (DSC) and the activation energy for precipitation of Si was obtained through Kissinger analysis. The precipitation behaviour of Supersaturated Si in both samples was further examined by TEM. It was found that Si mainly precipitated inside the grains in Al-1 wt-%Si alloy. while in Al-4 wt-%Si alloy. nearly all the Si precipitates distributed along the grain boundaries. This may be due to the structure difference between the alloys in as-quenched state展开更多
文摘The main features of martensite transformation in melt-quenched Fe-31.4% Ni alloy on cooling below room temperature have been studied. It is found that the ribbon 50～60 μm thick, prepared by spinning technique, is a natural composite in which isothermal and surface martensite are not formed, while athermal martensite forms at lower temperature, all factors being the same, as compared to the alloy of the same composition and grain size, prepared by recrystallization.
基金Supported by the State Key L aboratory of Coal Conversion ICC CAS and the Key L aboratory of Science and Technology of Controllable Chemical Reactions BU CT of Ministry of Education of China
文摘Surface morphology, physical-chemical properties of skeletal iron catalysts prepared by leaching of the rapidly quenched(RQ) and naturally quenched(NQ) Fe-Al alloys with an aqueous solution of NaOH were characterized by using a series of techniques including XRD, BET, XPS, SEM, H_2 and CO-TPD. It was found that the RQ skeletal iron catalyst exhibits a smaller particle size, larger specific surface area and pore volume than the NQ one. The H_2 and CO-TPD experiments showed that the RQ skeletal iron exhibits stronger affinity for H_2 and milder affinity for CO compared with the NQ one. But the NQ skeletal catalyst shows a better thermal stability than the RQ catalyst.
文摘The structure of rapldly quenched Al-Si alloys (1 and 4 wt-%Si) was systematically studied by optical and transmission electron microscopy (TEM ) as welI as X-ray djffractjon (XRD). ExperimentaIresults show that rapid solidification refines the grain size. extends the solid solubility of Si in Al and Introduces a high density ot defects which exist in the forms of vacancies, dislocations and dislocation loops. etc.. The decomposition process of the alloys was fol lowed by using differential scanning calorimeter (DSC) and the activation energy for precipitation of Si was obtained through Kissinger analysis. The precipitation behaviour of Supersaturated Si in both samples was further examined by TEM. It was found that Si mainly precipitated inside the grains in Al-1 wt-%Si alloy. while in Al-4 wt-%Si alloy. nearly all the Si precipitates distributed along the grain boundaries. This may be due to the structure difference between the alloys in as-quenched state
