YAO Daping HU Zhuangqi LI Yiyi ZHANG Yun and SHI Changxu Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China.
材料科学技术（英）
In this paper,the activation energy for precipi- tate dissolution in binary AI-Li alloy has been in- vestigated by considering precipitate dissolution in Al-Li alloy,continuously heated as a thermally ac- tivated process.The proposed calculation was car- ried out by changing the scanning rate in DSC measurement.The results show that the formation of GP zone is easy because the activation energy for its dissolution is smaller than that for Li atom diffu- sion in the matrix.The δ′dissolution consists of two steps:the first step needs larger thermal activation to break down the superlattice structure,and the second is much easier like GP zone dissolution.The phase is the most stable,which needs much larger thermal activation to disappear.
关键词:
Al-Li alloy
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null
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null
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null
XIAO Jichuang FANG Jianneng South China University of Technology
,
Guangzhou
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China XIAO Jichuang Associate Professor
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Dept.of Mechanical Engineering No.2
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South China University of Technology
,
Guangzhou 510641
,
China
金属学报(英文版)
An investigation was made of the influence of Zr additive on the high temperature phase trans- formations,martensitic forward/reverse transformations,and shape memory effect of Cu-Zn-Al base alloys by means of differential scanning calorimetry(DSC),X-ray diffraction and TEM.It was found that an addition of 0.35 wt-% Zn could effectively inhibit the precipitation of α and γ phases and hence promote the order-martensitic transformations β_2→DO_3→18RM,thus resulting in a minimum activation energy of the martensitic trans- formation and narrow temperature ranges(M_s-M_f)and(A_s-A_f);the alloy so obtained pos- sessed smooth and mobile martensite intervariant interfaces,therefore showing the best shape memory effect.
关键词:
Cu-Zn-Al alloy
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null
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null
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null
LIN Junshan
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LI Pengxing
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WU Renjie Shanghai Jiao Tong University
,
Shanghai
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China postdoctoral
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Institute of Composite Materials
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Shanghai Jiaotong University
,
Shanghai 200030
,
China
金属学报(英文版)
The differential scanning calorimetric(DSC) and transmission electron microanalysis (TEM) techniques were used to study the kinetic process of precipitation in matrix of cast SiC_p/2024 composites.The results showed that precipitation reactions of GP zone and intermediate phase S'(Al_2CuMg)in the composites were accelerated compared with SiC-free material,the peak temperatures of both reactions were decreased.The reaction enthalpies of both the GP zone and intermediate phase S' formation in the matrix were substantially decreased after the addition of SiC.TEM analysis found that the alloying element Mg segregated at the SiC/Al interfaces,and was depleted in the matrix near the interface.The precipitation-free zones(PFZ) and precipitation-sparse zones(PSZ) formed near the interfaces,as a results,the volume fraction of precipitates in matrix was reduced.
关键词:
SiC_p/2024 composite
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null
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null
朱妮娜
,
林涛
,
甘卫平
,
郭桂全
电镀与涂饰
以双酚A型环氧树脂E-44为粘接相，以QNP1(端叔胺基超支化聚酯复合物)为潜伏性固化剂，采用非等温示差扫描量热法(DSC)研究了E-44/QNP1体系的固化行为，以55%银粉为导电填料，研究了固化反应时间对导电浆料电性能的影响。E-44/QNP1体系在25~200°C范围内的固化反应热力学研究结果表明，固化剂QNP1的最佳用量为25%，并根据Kissinger和Crane方程拟合出固化反应动力学方程；在110°C/20 min最优固化条件下制备的E-44/QNP1导电银浆，其固化膜的电阻率最小，为3.5×10?5?·cm，可以满足硅异质结太阳能电池顶部电网电极银浆的应用要求。
关键词:
导电银浆
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双酚A型环氧树脂
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固化反应动力学
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电阻率
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太阳能电池
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示差扫描量热法
任志刚
,
罗潘
,
徐阳
,
叶宽
,
冯义
,
徐曼
,
李华春
,
任文娥
,
王立
绝缘材料
通过对北京地区的多根退役110 kV及220 kV交联聚乙烯电缆绝缘层进行差示扫描量热、热失重和傅里叶红外光谱等分析,研究了绝缘材料的聚集态结构及热稳定性.结果表明:电缆带电运行使XLPE的熔程变宽,带电运行的时间与材料的结晶度没有明显的关系.热失重和傅里叶红外光谱结果反映出退役XLPE电缆中只有少数试样发生了一定程度的热氧老化,大多数电缆绝缘层没有发生明显的热氧老化.
关键词:
交联聚乙烯
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聚集态结构
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差示扫描量热法
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热重法
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红外法
刘宏
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胡彩玲
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刘碧雄
涂料工业
用差示扫描量热法(DSC)对聚酯/TGIC铝型材专用粉末涂料的非等温固化反应进行了研究,分析了粉末涂料固化反应过程,采用温度-升温速率图外推法确定了该体系的特征参数凝胶温度(To)、固化温度(Tp)和后处理温度(Tf)分别为122 ℃、150℃、206℃;通过DSC测试分析,确定了该体系粉末涂料的最低固化温度为120℃左右,静电喷涂较佳的固化工艺参数为200℃/20 min,为铝型材粉末涂料静电喷涂固化工艺过程控制的确定提供了重要的参考依据.
关键词:
粉末涂料
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差示扫描量热法
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固化工艺过程
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分析
徐亚娟
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周思凯
,
廖功雄
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蹇锡高
高分子材料科学与工程
采用非等温差示扫描量热仪(DSC)对环氧树脂(E-51)/杂萘联苯聚芳醚酮(PPEK)共混物的固化过程进行研究.利用T-β外推法确定了固化工艺温度,并利用Kissinger和Crane法计算得到共混体系固化反应的表观活化能Ea、指前因子A、固化反应级数n等动力学参数.结果表明,PPEK的加入对环氧树脂的固化反应温度影响不大,但反应活化能有所升高,表明PPEK的加入阻碍了固化反应的进行.通过固化度与固化时间的关系曲线证明,PPEK的加入不改变环氧树脂的固化反应机理.
关键词:
杂萘联苯聚醚酮
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环氧树脂
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固化动力学
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差示扫描量热仪
居俊杰
,
谢邦互
,
杨伟
,
杨鸣波
高分子材料科学与工程
采用熔融共混的方法将高密度聚乙烯(HDPE)5000S与自制的分子链调控聚乙烯(CMPE)共混制备得到了一系列分子量分布(MWD)不同的双峰聚乙烯(BPE)共混物.对共混物进行普通DSC、连续自成核退火热分级技术(SSA)、等温结晶等一系列测试.结果表明,CMPE的加入有利于提高5000S的结晶能力,能加快其结晶速度,并在一定程度上完善其晶体结构.同时在CMPE含量适当时,共混物厚晶片的厚度和厚晶片含量不会发生显著的降低.
关键词:
双峰聚乙烯
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差示扫描量热分析
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热分级
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等温结晶
吴霞
,
王继辉
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倪爱清
玻璃钢/复合材料
采用过氧化苯甲酰(BPO)与过氧化-2-乙基己酸叔丁酯(OT)组成复合引发体系,比较不同配比下的不饱和聚酯树脂(UPR)所制人造石英石的力学性能.应用差示扫描量热法(DSC)研究复合引发体系下UPR的不等温固化反应动力学性能,使用Kissinger方程及Crane方程对数据进行处理并得到UPR的固化动力学模型,并对所得模型加以验证和修正,修正后的模型与实验结果具有更好的一致性.
关键词:
差示扫描量热
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复合引发
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固化动力学
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人造石英石
