张康侯
,
陈黎莉
金属学报
<正> 在对Sm-Pd二元系相图的研究中,发现了化合物SmPd_5。在对Eu-Pd二元系相图的研究中,发现在EuPd_3和Pd之间存在一个化合物EuPd_x。按照Совицкий和陈念贻等人用化学键参数-计算机模式识别法提出的金属间化合物的晶型预报表,在Sm-Pd系和Eu-Pd系中都应存在AB_5型化合物,其结构均为CsCu_5型六方结构。但是,至今为止,化合物EuPd_5的存在一直未能验证,EuPd_5和SmPd_5的晶体结构也一直未能由实验确定。
关键词:
金属间化合物SmPd_5
,
EuPd_5
,
X-ray diffraction
,
crystal lattice
丁佳钰
,
肖瑗
,
王哲飞
,
王丽熙
,
张其土
无机材料学报
doi:10.3724/SP.J.1077.2010.10563
研究了CrO3、Nb2O5、SiO2及Al2O3对 Y2Ti2O7 陶瓷的烧结性能、相组成和微波介电性能的影响. 其中Nb2O5 掺杂能够降低 Y2Ti2O7 陶瓷材料的烧结温度, 提高基体陶瓷的介电常数和品质因子,引起谐振频率温度系数的明显变化. 且随着Nb2O5含量的增多,所有样品的主晶相仍为立方烧绿石型Y2Ti2O7,Nb5+可能进入烧绿石结构中, 部分取代Ti4+所在位置.实验结果表明：1mol%Nb2O5掺杂的陶瓷材料在 1420℃ 下烧结致密,具有最佳的微波介电性能: ε r =61.8, Q× f =9096GHz (f=5.494GHz), τf =54×10 - 6 /℃.
关键词:
陶瓷
,
crystal growth
,
X-ray diffraction
,
dielectric properties
,
modification
陈藜莉
,
张康侯
金属学报
采用X射线衍射,示差热分析和金相等方法研究了Nd-Pd系相图中含0—50at-％Nd的区域。发现在该区域内存在6个金属间化合物:NdPd_5,NdPd_3,NdPd_2,Nd_2Pd_3,Nd_1Pd_5和NdPd。其中,NdPd_3,Nd_4Pd_5和NdPd是固液共熔化合物。还测出NdPd_5为SmPt_5型结构,NdPd_?为AuCu_3型结构,低于708±4℃的NdPd为CrB型结构。在该区域内共有3个共晶反应和3个包晶反应。
关键词:
Nd-Pd二元系
,
phase diagram
,
X-ray diffraction
,
differential thermal analysis
栾卫志姜传海嵇宁
材料研究学报
通过X射线衍射线形分析表征了喷丸表面的组织结构, 利用原位拉伸X射线衍射应力分析研究了TiB2/6351Al复合材料喷丸表面基体的力学行为. 结果表明, 喷丸后复合材料表面基体的屈服强度提高了26\%, 整体强度提高约28%, 显微硬度提高50%以上. 喷丸前、后复合材料基体承载系数分别为81%和83%, 喷丸后的基体承载系数略有提高. 喷丸表面基体的晶块尺寸及位错密度分别约51 nm和3.05 X 1014m-2, 晶块细化及位错密度增高是导致表面基体力学性能提高的主要原因.
关键词:
复合材料
,
shot blasting
,
matrix mechanical properties
,
X-ray diffraction
,
metal matrix composite
,
microstructures
黄爱琴
,
李国勋
,
马淑兰
,
李国斌
,
余忠勤
材料研究学报
采用TG-DTA 热分析和X 射线衍射相结合的方法,研究了由不同原料制取单一相YBa2-Cu_3O_(7-(?))超导体的合成反应机理。试验结果表明,YBa2Cu_3O_(7-(?))的形成经历两个反应阶段,首先形成BaCuO_2和Y_2Cu_2O_5,随后这两个二元复合氧化物化合形成YBa2Cu_3O_(7-(?))。各步反应温度受钡盐种类控制,采用Ba(NO_3)_2原料,在750℃即可表现出超导性,T_c 达86K。
关键词:
YBa_2Cu_3O_(7-γ)
,
superconductor
,
synthetic mechanism
,
TG-DTA thermal analysis
,
X-ray diffraction
P. Fernandez G. Gonzalez I. Alfonso I.A. Figueroa
材料科学技术（英文）
Two ternary Al-2.2Zn-0.95Mg and Al-5.5Zn-2.1Mg (in wt pct) alloys, with Zn:Mg ratios close to 2.5 were produced by conventional ingot casting metallurgy. The ingots were solution heat treated at 500°C for 0.5 h and aged at 180°C for times between 0.5 and 80 h. The structural characterization was carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and Vickers microhardness measurements (HV). The study was focused on the investigation of the precipitates formation and the relationship between hardness and lattice parameter for α-Al. The results showed that there was an inverse correlation for all the experimental conditions, and the aged peaks coincided with lattice parameter minima. Significant precipitates formation only occurred for the alloy containing 5.5 wt pct Zn and 2.1 wt pct Mg, provoking an important strengthening and variations in the lattice parameter, however, this was not observed for the alloy containing 2.2 wt pct Zn and 0.95 wt pct Mg. A plausible explanation of the increment of hardness values could be the presence of a well distributed μ phase (MgZn2). At initial stages of the precipitation process, μ' was the most abundant precipitate while the phase τ was observed at overaged conditions. These results showed that the aging response of the conventionally cast Al-Zn-Mg alloys could be obtained using the lattice parameter of the α-Al matrix, even for alloy systems with low precipitates formation.
关键词:
Aluminum alloy
,
X-ray diffraction
,
Precipitation
,
Lattice parameter
,
Hardness
Wenhua SHI
,
Lei ZHAO
,
Liping LUO
,
Qiming WANG
材料科学技术（英文）
The fluctuations of the strained layer in a superlattice or quantum well can broaden the width of satellite peaks in double crystal X-ray diffraction (DCXRD) pattern. It is found that the width of the 0th peak is directly proportional to the fluctuation of the strained layer if the other related facts are ignored. By this method, the Ge-Si atomic interdiffusion in Ge nano-dots and wetting layers has been investigated by DCXRD. It is found that thermal annealing can activate Ge-Si atomic interdiffusion and the interdiffusion in the nano-dots area is much stronger than that in the wetting layer area. Therefore the fluctuation of the Ge layer decreases and the distribution of Ge atoms becomes homogeneous in the horizontal Ge (GeSi actually) layer, which make the width of the 0th peak narrow after annealing.
关键词:
X-ray diffraction
,
null
,
null
,
null
,
null
Liuding WANG
,
Junqiang ZHOU
,
Quanxi CAO
,
Zhao CHEN
材料科学技术（英文）
The intensity and position of sidebands (satellites) on both sides of main diffraction peak in a great number of X-ray diffraction profiles of alloys always change with progress of aging. The sidebands position is determined by a newly optimized Voigt function in present investigation. Furthermore, for Cu-4 wt pct Ti alloy aged at 400℃ for 720 min and 1080 min, after introducing the weight factor of above two satellites intensity, the relative error between the fitting curves and X-ray diffraction profiles is less than 0.185%, which is more precise than the previously calculating result.
关键词:
X-ray diffraction
,
null
,
null
,
null
