L.Y. Dai
,
B. Cao
,
M. Zhu
金属学报(英文版)
The cryogenic milling and milling in conjunction with dielectric barrier discharge plasma (DBDP) have been separately set up. The combined effect of low temperature and plasma on ball milling has been investigated by examining the refinement of particle size and grain size of iron powder using scanning electron microscopy, X-ray diffraction, and small angle X-ray scattering. It was found that the mean size of iron particles could reach 104nm only after 10 hours of ball milling in conjunction with DBDP, whereas a minimum average grain size of 8.4nm was obtained by cryomilling at －20℃; however, it is difficult to refine the particle size and grain size under the same milling condition in the absence of DBDP and cryogenic temperature.
关键词:
ball milling
,
null
,
null
张清
,
李全安
,
井晓天
,
张兴渊
材料工程
doi:10.3969/j.issn.1001-4381.2011.03.016
Mg24Y5相的细化是进一步提高Mg-l0Y合金力学性能的关键.研究了稀土元素sm对Mg-l0Y合金中的Mg24Y5相及其基体组织的细化作用,结果表明:sm的加人,改善了Mg24Y5相的形貌,促进了细小弥散分布的Mg24Y5颗粒相的形成;同时,Sm的加人,通过固溶作用,进一步细化了基体组织;显微组织的改善导致了合金高温下力学性能的提高.
关键词:
Sm
,
Mg-10Y合金
,
组织细化
,
力学性能
王龙妹
,
杜挺
金属学报
用直接平衡法研究了1500,1550,1600℃Ni液中Y-S平衡关系,测定了钇的脱硫常数lgK_(YS)及Y,S的一阶活度相互作用系数e_S~Y与温度的关系,并进行了有关的热力学计算。由测得的数据算出Ni液中YS的标准生成自由能△G_((Y)S),钇的标准溶解自由能△G_((Y)(l)→[Y]Ni),活度系数γ_Y~o,以及钇的克原子分数自相互作用系数∑_Y~Y和百分浓度自相互作用系数e_Y~Y与温度的关系。 对于反应[Y]_(Ni)+[S]_(Ni)=YS_(s) △G_((Y)S)=-215000+95.53T(cal/mol)脱硫常数: lgK_(YS)=-47000/T+20.86 e_S~Y=-350200/T+179 △G_((Y)(l)→[Y]Ni)=126200-79.31T(cal/mol) lgγ_(Y)=27584/T-15.151 ∑_Y~Y=-127T05/T+69.79 e_Y~Y=-364.8/T+0.2018
关键词:
LI Guodong
,
D U Ting
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China LI Guodong
,
Department No.16
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
100081
,
China
金属学报(英文版)
The thermodynamic properties of Cu-Ce-S and Cu-Y-S liquid solutions were studied by the chemical equilibrium technique at 1200℃. The equilibrium constants and the standard free energies of formation of CeS and YS were determined for the reactions: CeS=[Ce]+[S] and YS = [Y]+[S] . For the solution of Ce_(1) and Y_(l) in pure Cu according to the reactions: Ce_(1)= [Ce] and Y_(1)= [Y] , the standard free energies of solutions were obtained. The first order and second order interaction coefficients between solute elements as well as the activity coefficients γ_(Ce)~0 and γ_Y~0 in liquid Cu were also determined.
关键词:
Cu-Ce-S system
,
null
,
null
赵娟
,
李建平
,
郭永春
,
杨忠
,
杨觉明
,
梁民宪
稀有金属材料与工程
用相图计算软件Pandat计算了Mg-Gd-Y合金的液相面投影图、室温(25℃)的等温截面图、Mg-xGd-2Y和Mg-xGd-7Y合金系的垂直截面图,并选取了Mg-5Gd-2Y和Mg-1Gd-7Y两种合金,通过相图计算与实验验证相结合的方法对合金的相平衡及凝固过程进行了研究.用光学显微镜、扫描电镜、能谱仪及示差扫描量热仪对该合金的室温平衡相组成及凝固过程的相变温度点进行了验证.结果表明,相平衡热力学计算结果与实验结果吻合,Mg-5Gd-2Y合金的凝固顺序为L-L+α-Mg-α-Mg+Mg5Gd-α-Mg+Mg24Y5+Mg5Gd;Mg-1Gd-7Y合金的凝固顺序为L--L+α-Mg-α-Mg+Mg24Y5--α-Mg+Mg24Y5+Mg5Gd,两合金的室温平衡组织均为α-Mg+Mg24Y5+MgM5Gd.
关键词:
相图计算
,
Pandat软件
,
Mg-Gd-Y相图
,
Mg-5Gd-2Y
,
Mg-1Gd-7Y
娄玲
,
尹静波
,
高战团
,
梁奇志
,
董丽松
,
陈学思
,
景遐斌
高分子材料科学与工程
从左旋L-乳酸经高温催化反应得到低聚L- 乳酸,再经高温裂解减压蒸馏制得单体L-丙交酯(LLA),理论收率高达80%以上.LLA经纯化,再以辛酸亚锡为催化剂开环聚合得到聚L-丙交酯(聚L-乳酸,PLLA),其粘均分子量可达到40万.
关键词:
L-丙交酯
,
聚乳酸
,
生物降解材料
Superconductor Science & Technology
The spin-Hamiltonian parameters (g factors g(parallel to) and g(perpendicular to) and zero-field splittings b(2)(0), b(4)(0), b(4)(4), b(6)(0) and b(6)(4)) for Gd3+ ions at the tetragonal Y3+ site of YBa2Cu3O6+y (y = 0.06) superconductor are calculated together from a diagonalization (of the energy matrix) method based on the one-electron crystal field mechanism. In the method, a 56 x 56 energy matrix concerning the ground multiplet S-8(7/2) and the excited multiplets L-8(7/2) (where L = P, D, F, G, H, I) for 4f(7) ions at a tetragonal crystal field and under an external magnetic field is constructed and used. The crystal field parameters B-k(q) in the energy matrix are obtained from the superposition model. The calculated results are in reasonable agreement with the experimental values. The defect structure (characterized by the angular distortion Delta theta) of the Gd3+ impurity centers in YBa2Cu3O6+y is also acquired from the calculation. The results are discussed.
关键词:
electron-paramagnetic-resonance;superposition-model analysis;crystal-field parameters;single-crystals;epr-spectra;magnetic-field;energy-levels;ions;gd3+;temperature
杨广宇
,
刘咏
,
王岩
,
李建波
,
唐蓓
,
李慧中
中国有色金属学报
采用光学显微镜、扫描电镜及透射电镜研究微量B和Y对铸造Ti-AIl-Nb-W合金显微组织的影响.结果表明:Ti-47Al-4Nb-0.6W合金的基本凝固路线为L→β+L→(β+a)+L→(β+a)+γ→aa+γ→(a-γL)+γ→(a2+γ<,L>)+γ,添加微量B和Y并未改变其基本凝固路径;微量B元素在合金中以短棒状TiB2相存在,细化了铸造Ti-47Al-4Nb-0.6W合金的晶团尺寸及片层间距;微量稀土Y元素主要以Y2O3氧化物颗粒的形式分布于片层晶团界面处,在B和Y的共同作用下,合金的片层晶团尺寸以及片层间距进一步减小.
关键词:
TiAl基合金
,
显微组织
,
铸造合金
,
B
,
Y
骆良顺
,
刘桐
,
张延宁
,
苏彦庆
,
郭景杰
,
傅恒志
金属学报
doi:10.11900/0412.1961.2015.00619
对Al-15％Y(质量分数)过共晶合金在1～100 μm/s的抽拉速率下进行定向凝固实验,研究抽拉速率对组织演化及Al3Y相生长规律的影响.结果表明,铸态Al-15％Y合金主要由Al3Y先析出相和A13Y/Al共晶体组成.在定向凝固过程中,当抽拉速率为l μm/s时,Al3Y相为不规则形状且边界清晰,为小平面的生长特性.随着抽拉速率的增加,Al3Y相的形貌逐渐转变为拉长的六棱柱形态,其中少量的Al3Y相具有中空形貌.当抽拉速率为10和20 μm/s时,A13Y相按粗大的六棱柱形态生长.进一步增加抽拉速率至100μm/s时,组织中出现“十”字形貌的Al3Y相,为2个六棱柱垂直交叉结构,类似枝晶的生长形式.在抽拉速率增加的过程中,固/液界面前沿逐渐出现领先相,且凝固速率越大,领先距离越长.
关键词:
Al-Y过共晶合金
,
定向凝固
,
金属间化合物Al3Y
,
组织演化
