鲁小叶
金属学报
用透射电镜,X射线衍射仪和电阻法研究了Cu-14.84wt-％Zn-7.75wt-％Al形状记忆合金在直接淬火和分级淬火后马氏体的稳定性。试验结果表明,直接淬火和分级淬火(150℃,2min)后于室温时效约3h的马氏体均为M18R结构,但刚直接淬火后马氏体并不稳定,其某些衍射峰位置和电阻率均随室温时效而变化;而分级淬火(150℃,2min)后马氏体是稳定的,其所有衍射峰位置和电阻率几乎不随室温时效而变化。上述结果可用“马氏体再有序化机制”解释。
关键词:
Cu-Zn-Al合金
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shape memory alloy
,
martensite
,
stabilization
LU Xiaoye Central south University of Technology
,
Changsha
,
China Lecturer
,
Dept.of Materials Science and Engineering
,
Central South University of Technology
,
Changsha 410083
,
China
金属学报(英文版)
The stability of thermoelastic martensite in a Cu-14.84 wt-%Zn-7.75 wt-%Al shape mem- ory alloy with M_s=106°C after direct quenching or stepped quenching has been investigated by using TEM,X-ray diffroctometer and double electric bridge instrument.The martensite aged for about 3 h at room temperature after either direct quenching or stepped quenching (150°C,2 rain)is the M18R structure.The martensite just directly quenched is not so stable, both its certain diffraction peaks and specific electric resistivity,change with aging at room temperature;whereas it is stable after stepped quenching(150°C.2 min),and its diffraction peaks and specific electric resistivity change no more with aging at room temperature.The above mentioned results seem to be explained by the martensite reordering.
关键词:
Cu-Zn-Al alloy
,
null
,
null
,
null
WANG Mingpu
,
LIU Jinwen Central South University of Technology
,
Changsha
,
China Lecturer
,
Dept.of Materials Science and Engineering
,
Central South University of Technology
,
Changsha 410083
,
China
金属学报(英文版)
The stabilization of thermoelastic martensite in a rapidly solidified Cu-Zn-A1 alloy is be- lieved to be the process of disordering in atomic configuration during which the structure of martensite gradually transforms into N9R(b/a=1/3~(1/2))from M18R.This is dependent upon the intrinsic decomposition tendency of the martensite.
关键词:
Cu-Zn-Al alloy
,
null
,
null
,
null
QI Xuan JIANG Bohong XU Zuyao(T.Y.HSU) Shanghai Jiaotong University
,
Shanghai.China Qi Xuan
,
Dept.Marter.Sci.and Eng.
,
Shanghai Jiaotong University
,
Shanghai
,
China
金属学报(英文版)
The correlation between the shape memory effect(SME)and the ordering degree in martensite formed through various heat-treatment processes,e.g.ice water quenching, step-quenching and aging etc.,has been studied in a Cu-26Zn-4Al alloy.The martensite or- dering degree is estimated by △d,the spacing difference of some pairs of diffracting planes with indices satisfying a relation of(h_1~2-h_2~2)/3=(k_2~2-k_1~2)/n(n=1 for 9R martensite,n=4 for 18R martensite).M 18R martensite is obtained from step-quenching,in which the value of △d increases with the holding duration of step-quenching,and the shape recovery rate η increases synchronouslly.9R martensite is obtained from direct water-quenching,the value of △d is quite large and SME is also good at just quenching state.But both △d and η decrease continuously with aging time at room temperature.This stabilization phe- nomenon of martensite is explained by the observation of TEM lattice fringe image,and it may be attributed to the clustering of quenched-in supersaturated vacancies at (001)_M close-packed plane in martensite and decreasing the ordering degree.A reduction in △d and η occuring in the specimens on step-quenching or aging at higher temperature, which may be related to the precipitation of the α-phase and the enrichment of solute atoms, decreases the ordering degree.
关键词:
Cu-Zn-Al alloy
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null
,
null
,
null
,
null
刘杰
,
张月义
,
马兆昆
,
梁节英
高分子材料科学与工程
借用傅里叶变换红外光谱（FT-IR）、元素分析（EA）、X射线衍射（XRD）和示差扫描量热分析（DSC）等手段,对比研究了热氧稳定化过程中250℃下时间效应与两种聚丙烯腈（PAN）共聚纤维及其炭纤维结构和性能之间的关联。研究结果表明,PAN纤维在250℃温区内停留超过9min时,最终热氧稳定化纤维的环化度（RCI）、体密度和芳构化指数（AI）的增加速率开始变小;炭纤维的孔含量（Vp）值与内部微晶的d002值开始增大,微晶排列的规整程度变差,缺陷增多,拉伸强度开始降低。
关键词:
聚丙烯腈
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热氧稳定化
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炭纤维
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时间
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孔含量
李端阳
,
袁静
,
李松
,
秦高梧
金属功能材料
doi:10.13228/j.boyuan.issn1005-8192.2015052
Ti3SiC2金属间化合物综合了金属和陶瓷诸多优异性能,具有低密度、高弹性模量、高强度和高稳定性,同时表现出良好的塑性,是热和电的良导体,易于机械加工,抗热震性优良.为制备Ti3SiC2多孔材料,系统研究了Ti3 SiC2浆料的性质,通过水解和电动力学实验研究,结果表明,未添加分散剂的Ti3SiC2悬浮液在pH=4～11范围内很难保持浆料的稳定性.添加干粉质量分数为1％和1.5％的PEI可使Ti3SiC2悬浮液在pH=4～8范围内具有很高的稳定性.并在此工作的基础上,以聚氨酯海绵为模板,采用有机浸渍法及随后的高温煅烧获得了Ti3SiC2多孔材料.
关键词:
多孔材料
,
MAX相
,
Zeta电位
,
分散性
,
稳定性
王飞
,
王浩江
,
刘煜
,
杨育农
合成材料老化与应用
针对聚甲醛（ POM）热稳定性较差的问题，研究了抗氧剂、吸醛吸酸剂和成核剂对其长期热氧稳定化的影响。结果表明，经120℃/1000h的热氧老化后，吸醛剂K-3对POM的断裂伸长率保持率的改善最为明显，达99.5％；成核剂则在保持POM力学性能的基础上，有效降低了热氧老化后的b值，显示了优异的长期热氧稳定化作用。
关键词:
聚甲醛
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稳定化
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热氧老化
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成核剂
熊晨熙
,
彭向和
,
易成建
功能材料
鉴于油酸和月桂酸2种表面活性剂对磁流变液稳定性所起到的不同的作用,制备了若干种不同配比的以油酸和月桂酸共同添加的磁流变液,测量它们的零场粘度、力学性能和沉降率-时间曲线,研究了月桂酸、油酸和羰基铁粉3种成分的含量对于磁流变液稳定性和力学性能的影响。结果表明合理的添加油酸和月桂酸对于制备零场粘度小且稳定性优良的磁流变液具有显著的效果。
关键词:
磁流变液
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油酸
,
月桂酸
,
稳定性
胡秀颖
,
王成国
,
于美杰
,
王雯
,
卢文博
,
井敏
,
朱波
,
王延相
,
王启芬
功能材料
预氧化各温区纤维经超声蚀刻处理后,利用扫描电镜（SEM）观察其皮层和芯部的形貌差异,并借助Raman光谱证实了预氧化纤维皮层和芯部的化学结构差异。结果表明预氧化初期195～225℃预氧化纤维整体预氧化程度低,纤维皮层和芯部的结构几乎没有差异;预氧化中后期235～265℃预氧化纤维芯部的稳定化程度较皮层低,芯部被蚀刻溶解,皮、芯形貌差异明显;经275℃预氧化后,纤维芯部稳定化程度提高,无论皮层还是芯部都呈现不溶性;最终的预氧化纤维出现了宽化的石墨特征Raman散射峰,但皮层的衍射峰较芯部更为宽化,反映出皮、芯化学结构的差异。
关键词:
聚丙烯腈纤维
,
预氧化
,
超声蚀刻
,
皮芯结构
,
化学结构
王晓红
,
欧阳琴
,
陈友汜
,
王雪飞
,
李德宏
,
杨建行
,
潘建国
高分子材料科学与工程
采用K2S2O8-NaHSO3引发剂和水相沉淀聚合法制备了丙烯腈均聚物(PAN)、丙烯腈-β-衣康酸单乙酯共聚物(P(AN-MIA))、丙烯腈-表康酸共聚物(P(AN-IA)).采用红外光谱和差示扫描量热/热重同步分析研究了衣康酸α,β羧基对热稳定化反应的影响及机理.结果表明,引入MIA和IA共聚单体均能显著提高相对环化率,降低热稳定化反应起始温度,缓和放热和失重行为.但IA的作用效果更好,这归功于IA中的α,β羧基均能引发氰基发生离子环化反应,使PAN转变为更稳定的梯形结构.通过对空气气氛的差示扫描量热曲线进行分峰处理,研究了IA的α,β羧基对离子环化反应和氧化反应的影响及其机理.
关键词:
聚丙烯腈
,
衣康酸
,
羧基
,
热稳定化
