The chemical short-range order of Al-Fe-Ce amorphous alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It is found that the prepeak position in X-ray diffraction intens...The chemical short-range order of Al-Fe-Ce amorphous alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It is found that the prepeak position in X-ray diffraction intensity curve shifts to higher angles as the content of Fe increases, but it shifts to smaller angles as the content of Ce increases. The crystallization character of the amorphous alloy changes with the variation of the content of Fe and Ce. Ce can improve the interaction between atoms and the capacity of compound formation, so it is favorable to Al-based glass formability.展开更多
在较慢冷却条件下,Al-Fe合金熔体中面心立方结构的近程有序原子集团占主导地位。基于EET(empirical electron theory of solids and molecules)理论,计算了Al-Fe-Ce合金熔体中fcc结构近程有序原子集团Al-Fe,Al-Ce,Al-Fe-Ce,α-Al和主要...在较慢冷却条件下,Al-Fe合金熔体中面心立方结构的近程有序原子集团占主导地位。基于EET(empirical electron theory of solids and molecules)理论,计算了Al-Fe-Ce合金熔体中fcc结构近程有序原子集团Al-Fe,Al-Ce,Al-Fe-Ce,α-Al和主要析出相Al3Fe,Al6Fe,Al8Fe4Ce和Al4Ce的价电子结构,分析了Ce对Al-Fe合金熔体和主要强化相形成的影响。研究发现:Al-Fe最强键的n1α-Al--Fe(n1为共价电子对数)比α-Al的n1α-Al大14.2%,Al-Fe近程有序原子集团为二元AlFe相的形成提供了形核条件。Al-Ce,Al-Fe-Ce最强键的n1α-Al-Ce,n1α-Al-Fe-Ce分别比AlFe的n1α-Al-Fe大38.2%,39.3%,Ce添加促进了Al-Ce,Al-Fe-Ce原子集团的形成,减少了Al-Fe原子集团,为AlCe,AlFeCe相的形成提供了形核条件。对于Al-Fe合金,由于FAl6Fe(F为结构单元总成键能力)小于FAl3Fe,所以Al6Fe相优先形成。对于Al-Fe-Ce合金,由于FAl8Fe4Ce<FAl4Ce<FAl6Fe,所以优先形成的细小短棒状Al8Fe4Ce相可消耗Fe原子,进而减少了粗大针状、团球状Al3Fe,Al6Fe相的形成。Al8Fe4Ce最强键的n1Al8Fe4Ce与Al3Fe最强键的n1Al3Fe相近,Al4Ce最强键的n1Al4Ce与Al6Fe最强键的n1Al6Fe相近。Al4Ce强弱键键合力差距较大,Al8Fe4Ce键络分布较均匀,不存薄弱键合环节。展开更多
Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically inves...Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.展开更多
The microstructures of liquid and amorphous Al 90 Fe 5Ce 5 alloys were studied by X ray diffraction (XRD), and the crystalline behavior of the amorphous alloy was also investigated by differential scanning calorimetry...The microstructures of liquid and amorphous Al 90 Fe 5Ce 5 alloys were studied by X ray diffraction (XRD), and the crystalline behavior of the amorphous alloy was also investigated by differential scanning calorimetry (DSC). The distinct pre peaks were found on the structure factors of the liquid and amorphous alloys. The quenching temperature affects the pre peak area, but does not affect its position. The reduction of quenching temperature decreases the crystallization temperature and the activation energy of the Al Fe Ce amorphous alloy. Quenched from 1 050 ℃, a novel structure with a fine dispersion of Al nanophase particles homogeneously distributed in the amorphous matrix was obtained. And the sensitivity of the Al Fe Ce amorphous alloy to the quenching temperature reflects the micro inhomogeneity of the melt.展开更多
Rapidly solidified Al 8Fe 4Ce alloy was prepared by melt spinning.As quenched and as annealed microstructures were studied by TEM and energy dispersive spectrum analysis.The microhardness of the alloy at different...Rapidly solidified Al 8Fe 4Ce alloy was prepared by melt spinning.As quenched and as annealed microstructures were studied by TEM and energy dispersive spectrum analysis.The microhardness of the alloy at different annealing temperature was measured.The results obtained indicated that as quenched microstructure varied with different cooling rates.The microstructure annealed at 300℃ was much the same as that of the as quenched.The dispersed phases at grain boundary of the microstructure annealed at 400℃ became coarsening.After annealing at 450℃ for 2 hours,the primary phase and the intercellular dispersed phases,metastable phase Al 6Fe and Al 20 Fe 5Ce respectively,coarsened further.The soften temperature was deduced at over 300℃ by measuring microhardness.展开更多
文摘The chemical short-range order of Al-Fe-Ce amorphous alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It is found that the prepeak position in X-ray diffraction intensity curve shifts to higher angles as the content of Fe increases, but it shifts to smaller angles as the content of Ce increases. The crystallization character of the amorphous alloy changes with the variation of the content of Fe and Ce. Ce can improve the interaction between atoms and the capacity of compound formation, so it is favorable to Al-based glass formability.
文摘在较慢冷却条件下,Al-Fe合金熔体中面心立方结构的近程有序原子集团占主导地位。基于EET(empirical electron theory of solids and molecules)理论,计算了Al-Fe-Ce合金熔体中fcc结构近程有序原子集团Al-Fe,Al-Ce,Al-Fe-Ce,α-Al和主要析出相Al3Fe,Al6Fe,Al8Fe4Ce和Al4Ce的价电子结构,分析了Ce对Al-Fe合金熔体和主要强化相形成的影响。研究发现:Al-Fe最强键的n1α-Al--Fe(n1为共价电子对数)比α-Al的n1α-Al大14.2%,Al-Fe近程有序原子集团为二元AlFe相的形成提供了形核条件。Al-Ce,Al-Fe-Ce最强键的n1α-Al-Ce,n1α-Al-Fe-Ce分别比AlFe的n1α-Al-Fe大38.2%,39.3%,Ce添加促进了Al-Ce,Al-Fe-Ce原子集团的形成,减少了Al-Fe原子集团,为AlCe,AlFeCe相的形成提供了形核条件。对于Al-Fe合金,由于FAl6Fe(F为结构单元总成键能力)小于FAl3Fe,所以Al6Fe相优先形成。对于Al-Fe-Ce合金,由于FAl8Fe4Ce<FAl4Ce<FAl6Fe,所以优先形成的细小短棒状Al8Fe4Ce相可消耗Fe原子,进而减少了粗大针状、团球状Al3Fe,Al6Fe相的形成。Al8Fe4Ce最强键的n1Al8Fe4Ce与Al3Fe最强键的n1Al3Fe相近,Al4Ce最强键的n1Al4Ce与Al6Fe最强键的n1Al6Fe相近。Al4Ce强弱键键合力差距较大,Al8Fe4Ce键络分布较均匀,不存薄弱键合环节。
基金financially supported by the National Natural Science Foundation of China(No.52174363)the GDAS Project of Science and Technology Development,China(No.2019GDASYL-0203002)+2 种基金the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)the Science and Technology Project of Zhaoqing City,China(Nos.2021C003,2018K006)the Development of Key Technologies for Material and Microstructure Control of High Thermal Conductivity Casting Aluminum Alloy,China(No.2014A030313221)。
文摘Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.
文摘The microstructures of liquid and amorphous Al 90 Fe 5Ce 5 alloys were studied by X ray diffraction (XRD), and the crystalline behavior of the amorphous alloy was also investigated by differential scanning calorimetry (DSC). The distinct pre peaks were found on the structure factors of the liquid and amorphous alloys. The quenching temperature affects the pre peak area, but does not affect its position. The reduction of quenching temperature decreases the crystallization temperature and the activation energy of the Al Fe Ce amorphous alloy. Quenched from 1 050 ℃, a novel structure with a fine dispersion of Al nanophase particles homogeneously distributed in the amorphous matrix was obtained. And the sensitivity of the Al Fe Ce amorphous alloy to the quenching temperature reflects the micro inhomogeneity of the melt.
文摘Rapidly solidified Al 8Fe 4Ce alloy was prepared by melt spinning.As quenched and as annealed microstructures were studied by TEM and energy dispersive spectrum analysis.The microhardness of the alloy at different annealing temperature was measured.The results obtained indicated that as quenched microstructure varied with different cooling rates.The microstructure annealed at 300℃ was much the same as that of the as quenched.The dispersed phases at grain boundary of the microstructure annealed at 400℃ became coarsening.After annealing at 450℃ for 2 hours,the primary phase and the intercellular dispersed phases,metastable phase Al 6Fe and Al 20 Fe 5Ce respectively,coarsened further.The soften temperature was deduced at over 300℃ by measuring microhardness.
