肖晓玲
,
罗承萍
,
聂建峰
,
B.C.Muddle
金属学报
应用透射电镜研究了时效AZ91Mg-Al合金连续析出相的显微组织形态及晶体学特征.发现四种不同形态和晶体学特征的β-(Mg17Al12)析出相,其中占绝大多数的是板条状析出相.沿基面(0001)α析出的板条析出相与基体保持Burgers位向关系,生长方向为[7,2, ,0];其晶体学特征与由不变线应变原理预测的完全一致.第二类析出相是以其轴线与基面垂直的六棱柱体,六个棱柱面都是{ 100}αⅣ{ 10}β,与基体保持对称性好的Crawley位向关系.另有少量短棒状析出相与基体保持Porter位向关系.实验中还观察到一种未见报道过的位向关系.讨论了形成不同形态和晶体学特征的机制.
关键词:
AZ91
,
null
,
null
罗承萍
,
肖晓玲
,
刘江文
,
聂建峰
,
B.C.Muddle
金属学报
应用透射电镜(TEM)研究了时效AZ91 Mg-Al合金中三种形态的γ-Mg17Al12析出相(bcc)的多重位向关系及析出相颗粒间的{112}γ伪孪晶关系.这三种板条状、六棱柱状或短棒状的析出相分别与Mg基体(hcp)保持Burgers,Crawley和Porter位向关系;在同种析出相颗粒之间或异种颗粒之间能形成不具有孪晶结构特征的{112}γ伪孪晶关系.从晶体学角度解释了这种多重位向关系及伪孪晶的生成机制.并从单个析出相与基体间的匹配程度解释了这三种析出相的析出密度存在较大差别的原因.
关键词:
Mg-Al合金
,
null
肖晓玲
,
罗承萍
,
聂建峰
,
B.C.Muddle
金属学报
doi:10.3321/j.issn:0412-1961.2001.01.001
应用透射电镜研究了时效AZ91 Mg-Al合金连续析出相的显微组织形态及晶体学特征.发现四种不同形态和晶体学特征的β-(Mg17Al12)析出相,其中占绝大多数的是板条状析出相.沿基面(0001)α析出的板条析出相与基体保持Burgers位向关系,生长方向为[7,2,9,0];其晶体学特征与由不变线应变原理预测的完全一致.第二类析出相是以其轴线与基面垂直的六棱柱体,六个棱柱面都是{1100}αⅣ{110}β,与基体保持对称性好的Crawley位向关系.另有少量短棒状析出相与基体保持Porter位向关系.实验中还观察到一种未见报道过的位向关系.讨论了形成不同形态和晶体学特征的机制.
关键词:
AZ91 Mg-Al合金,β-(Mg17Al12)析出相,透射电镜分析,晶体学特征,不变线应变
Journal of Alloys and Compounds
Nd-Fe-(B.C) alloys have been synthesized by mechanical alloying and subsequent heat-treatment, with B4C as one of the starting materials. It is found that when the pure B4C is milled alone, it proves difficult to decompose. When the B4C compound is milled with Nd and Fe, the complete decomposition of B4C and the formation of Nd2Fe14(B,C) phase is observed. Furthermore, the competition between B and C atoms for entering the Nd2Fe14B lattice. the effects of the B4C content on the structure and the magnetic properties of Nd2Fe14(B,C)-based alloys are investigated. A coercivity as high as 18.3 kOe and the maximum energy product of 10.4 MGOe have been achieved for the Nd-Fe-(B,C) alloys. (c) 2005 Elsevier B.V. All rights reserved.
关键词:
permanent magnets;mechanical alloying;fe-c alloys;permanent-magnets;r2fe14c;nd
刘建功
,
殷小玮
,
成来飞
,
张立同
,
王琴
复合材料学报
为了降低液硅渗透法制备C／C—SiC复合材料中残留Si的含量，采用浆料浸渗结合液硅渗透工艺制备B12（C，Si，B）3改性C／C—SiC复合材料。通过分析不同比例B4C—Si体系在不同温度的反应产物，确定了B12（C，Si，B）3的生成条件。结果表明：B4C和Si在1300℃开始反应，生成少量B12（C，Si，B）3和SiC，且B12（C，Si，B）3的生成量随反应温度的升高而增加；当B4C和Si的摩尔比为3：1、反应温度为1500℃时，产物为B12（C，Si，B）3和SiC液硅渗透法制备的C／C—SiC复合材料相组成为非晶态C、β-SiC和B12（C，Si，B）3，未见残留Si。
关键词:
复合材料
,
C
,
C—SiC
,
B12(C，Si，B)3
,
浆料浸渗
,
液硅渗透
Physics Letters A
The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy
Journal of Alloys and Compounds
A model for diffusion is applied to the Ni-Al system to optimize the mobility parameters for the 132-b.c.c. phase by fitting the experimentally obtained diffusivities. In the model, the activation energy for diffusion is expressed as a function of the degree of ordering which is evaluated from thermodynamic data. The diffusivities, from the model are used to simulate diffusion experiments. The results are compared with experimental data and it is concluded that the model can yield satisfactory prediction. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
intermetallics;diffusion;thermodynamic modeling;alloys;fe;interdiffusion;model
