Gaowu QIN
金属学报(英文版)
doi:10.1016/S1006-7191(08)60117-9
Co-X(X=Cr, Mo, W) magnetic thin films were prepared by using DC magnetron sputtering, and their structures were examined by using X-ray diffraction (XRD). The amorphous forming ability (AFA) of the three alloy systems was discussed based on thermodynamic calculation and experiments. The results show that the Co-Mo thin films exhibit the largest AFA among them, and the Co-W thin films are condition-dependent amorphous while the Co-Cr thin films are hard to be amorphous, which is consistent with the thermodynamic calculation. The difference in AFA for the alloys of these three systems is finally ascribed to three main factors: differences in electronegativity, electron density and atomic size between Co and X elements.
关键词:
Amorphous forming ability
,
Co-Cr
,
Co-Mo
,
Co-W
刘叔仪
金属学报
<正> 作为固体脆性断裂判据的J积分,其数值与其积分路径无关,这在文献中叫“守恒性”。这个守恒性已被推广到塑性断裂,这到底有否根据?本文目的是作这个问题的证明。未用原作者的方法,但由两个旋度判据得到应力应变函数行列式给出的一些否定结论,希望这对J积分应用条件的了解有所助益。1.弹塑性J积分守恒的条件 J积分
关键词:
Applied Physics Letters
A giant magnetocaloric effect was observed at room temperature in Mn(1-x)Cr(x)As compounds with x=0.006 and 0.01. The Cr dopant reduces (or even eliminates) the large thermal hysteresis of MnAs, while it lowers the first-order transition temperature from 313 K for MnAs to 265 K for Mn(0.99)Cr(0.01)As. Near the Curie temperature, a magnetic field induces a first-order phase transition from a ferromagnetic hexagonal phase to a paramagnetic orthorhombic phase, leading to a maximum value of Delta S(M) of 20.2 J/kg K at 267 K for a 5 T field change for Mn(0.99)Cr(0.01)As. The study on the Mn(1-x)Cr(x)As system may open an important field in searching proper materials for room-temperature magnetic refrigeration. (C) 2008 American Institute of Physics.
关键词:
magnetic entropy change;transition
彭可
,
易茂中
,
冉丽萍
,
葛毅成
稀有金属材料与工程
根据固体与分子经验电子理论(EET),利用平均原子模型对(Mo_(1-x),W_x)Si_2)固溶体进行价电子结构分析,并分别与MoSi_2和WSi_2基体进行比较.结果表明,随着x值的增加,(Mo_(1-x),W_x)Si_2固溶体的主干键络键能、最强键上共价电子数和共价电子总数百分比均逐渐增加,表明固溶体的熔点、硬度和强度均逐渐增加.
关键词:
(Mo_(1-x)
,
W_x)Si_2固溶体
,
价电子结构
,
EET理论
,
性能
袁江
,
宋新华
,
孙甲尧
,
龚航
航空材料学报
doi:10.11868/j.issn.1005-5053.2016.1.001
基于密度泛函理论的第一性原理，通过计算 RuAl 合金氧化物 Al2 O3和 RuO2的氧化能，考察过渡金属元素 X （X ＝W，Mo，、Cr）加入到 RuAl 合金后的占位及对氧化物 Al2 O3和 RuO2的结构稳定性影响。研究表明：经过渡金属元素 X 合金化后，Al2 O3和 RuO2的氧化能均有所增大，增大 Al2 O3氧化能的顺序为：W ＞Mo ＞Cr；增大 RuO2氧化能的顺序为：Mo ＞Cr ＞W，且 RuO2氧化能增大幅度大于 Al2 O3。通过态密度、电荷密度等因素的分析，阐明了 W 对提高 RuAl 抗氧化性能的根本原因是降低了 Al-O 和 Ru-O 的共价键特性，增加了 Al-O 和 Ru-O 的离子键特性；金属元素 X（X ＝W，Mo，Cr）可阻碍 RuAl 金属化合物发生内氧化过程，有利于在 RuAl 表面层的横向方向上形成连续性致密的 Al2 O3氧化层。
关键词:
RuAl
,
第一原理
,
抗氧化性能
,
稳定性
,
氧化能
朱杰武
,
柳永宁
,
许雁
,
冯耀荣
机械工程材料
doi:10.3969/j.issn.1000-3738.2005.06.007
在不同温度下测试了X70管线钢动态断裂韧度K1d、J1d和止裂韧度K1a以及夏氏V型缺口冲击韧度Ak,对三者的关系进行了分析.结果表明:温度和加载速率都对断裂韧度产生影响;加载速率变化引起的韧-脆断裂转变具有热激活特征,在热激活分析基础上,在应力强度因子速率K=15 MPa·m1/2s-1条件下,得出断裂韧度、止裂韧度和冲击韧度三者的关系:Ak=4.84×106T-2.8K1d(或K1a).可以用小试样Ak数据计算得到K1d和K1a.
关键词:
管线钢
,
断裂韧度
,
止裂韧度
,
韧-脆断裂转变
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
,
null
,
null
,
null
Journal of Applied Physics
The thermal stability, magnetocaloric effect, and refrigeration capacity (RC) of Gd-based Gd(65)Fe(20)Al(15-x)B(x) (x=0-7) glassy ribbons have been investigated. A relatively wide supercooled liquid region Delta T(x)(Delta T(x)=T(x)-T(g)) (50-80 K) and large reduced glass transition temperature T(rg)(T(rg)=T(g)/T(m)) (>0.63) are found in Gd(65)Fe(20)Al(15-x)B(x) glassy ribbons. The distinctive glass transition and sharp crystalline events as well as large values of Delta T(x) and T(rg) confirm the excellent glass forming ability of these alloys. The maximal magnetic entropy changes, -Delta S(M)(max), and RC values of the specimens are about 4.80-5.21 J/kg K and 700-800 J/kg under 50 kOe, respectively. These -Delta S(M)(max) values are comparable to or even higher than that of some reported bulk metallic glasses. Moreover, the larger RC values are due to the broad Delta S(M) peak (similar to 200 K), which is caused by the glassy structure. The large Delta S(M) and RC values make the Gd-based Gd(65)Fe(20)Al(15-x)B(x) glassy ribbons attractive candidates for magnetic refrigeration materials. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3335498]
关键词:
magnetic refrigeration;temperature;transition
