Huifen CHAI Zheng RUAN Quncheng FAN Dept.of Materials Science and Engineering
,
Xi'an Jiaotong University
,
Xi'an
,
710049
,
China
材料科学技术（英）
The prestrained metals show substantial asymmetry between tension and compression in addition to the softening under cyclic loading, thus the cyclic creep takes place at a load-control test. The soft- ening reflects the decrease in density of dislocation and total internal stress, and the creep implies the asymmetry in back stress between tension and compression, The mechanical behaviour of the soft- ening is similar for materials with different slip modes, but their features of creep differ significantly. The creep of planar slip Cu-Zn alloy exhibits“explosively”, while that of wavy slip Cu and low car- bon steel occurs continuously and slowly. The explanation of creep behaviour via the internal dislo- cation structure was presented in this paper. According to asymmetw behaviour, it can be concluded that the internal processes of softehing also strongly depend on the slip mode. In addition, under high stress amplitude the opposite asymmetries take place for Cu and Cu-Zn alloy, it indicates that asymmetric back stresses developed in pretension have been eliminated even though the density and the configuration of dislocations have not reached equilibrium.
关键词:
internal stress
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null
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null
CHAI Huifen RUAN Zheng FAN Quncheng (Xi'an Jiaotong University
,
Xi'an
,
China CHAI Huifen
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associate professor
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Department of Materials
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Xi'an Jiaotong University
,
Xi'an 710049
,
China
金属学报(英文版)
The cyclic behaviours of two prestrained materials with different slip modes have been com- pared.From the analysis of hysterisis loops,it is suggested that the decrease in back stress dominates the cyclic process of Cu-Zn alloy with planar slip mode,while the decrease in frictional stress is the main factor affecting the behaviour of Cu with wavy slip mode.The re- lation between the dislocation configuration and internal stress has been also discussed.By means of the relation just mentioned,the variations of dislocation configuration before and after fatigue of the two materials,the differences in their softening mechanism and mechani- cal behaviour could be interpreted.
关键词:
slip mode
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null
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null
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null
Kewei XU Jiawen HE Huijiu ZHOU Research Institute for Strength of Metals
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Xi'an Jiaotong University
,
Xi'an
,
710049
,
China
材料科学技术（英）
The measurement of internal stresses in a PACVD TiN film proved experimentally to be difficult by a conventional X-ray diffraction technique.The linear relationship between 2θ and sin~2(?) could hardly be reached in some cases.Nevertheless.a good confirmation between the variation of FWHM-sin~2(?) and 20-sin~2(?) was revealed for every nonlinear forms.It followed that the effect of nondistributed micro-strains might exist in plasma assisted vapor deposited films,which usually have a strong crystal orientation,and the method of effectively separating macro-stress and micro-strain must be applied for the precise determination of internal stresses in PACVD films.
关键词:
TiN film
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null
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null
黄庆学
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李海斌
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周存龙
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帅美荣
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刘光明
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马勤
材料热处理学报
研究热轧压下率对Q235A碳钢与304不锈钢复合板中碳钢组织的影响.结果表明:珠光体数量随压下率增加而增多,分布更加均匀,先共析铁素体随压下率先增加后减小.轧制形变试样产生内应力促进奥氏体的共析转变;碳原子从被压碎的晶粒内部向外部扩散,导致珠光体增加、先共析铁素体减少.轧制后晶粒细化及析出均匀的碳化物使材料抗拉强度提高.
关键词:
压下率
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内应力
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相变
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组织性能
张玥
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吴驰飞
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余木火
材料科学与工程学报
为了减少废弃饮料瓶片(回收聚对苯二甲酸乙二酯,rPET)与瓶盖(回收线性低密度聚乙烯,rLLDPE)共混物的内应力,采用反应挤出法制备新型增容剂rLLDPE与甲基丙烯酸缩水甘油酯接枝乙烯-辛烯共聚物(POE-g-GMA)的接枝共聚物,通过溶剂沉浸法和热焓松弛拟合来观察和计算共混物的链段松弛时间,并利用动态力学性能预测材料的使用寿命.结果显示共混物在60℃下热处理25h以后,样条应力发白现象减弱,与热焓松弛拟合结果一致.120℃下热处理10h后的共混物在130～180℃时符合时温等效原理和WLF方程.根据共混物老化活化能的变化确定老化临界失效时间,利用寿命方程计算得到共混物在25℃下的使用寿命为9.6年.
关键词:
废弃高分子
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内应力
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热处理
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热焓松弛
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使用寿命
付永忠
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程广贵
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王权
材料科学与工艺
通过磁控溅射方法制备了GeSbTe薄膜.借助原子力显微镜,X射线衍射仪和应力测试仪等仪器,并结合对薄膜表面形貌和晶体结构的分析,研究了溅射功率和退火温度对薄膜内应力的影响.结果表明：当溅射功率较小时,内应力随着溅射功率的增大而增大,在50W左右时达到最大值,随后又随着溅射功率的增大而减小.退火温度为160℃时,薄膜发生非晶态向fcc晶态结构的相变,由于Te原子析出到晶粒边界,导致薄膜的内应力急剧增大到最大值为100MPa左右,而后随着退火温度的升高而下降,fcc结构向hex结构转变时,内应力变化并不明显.
关键词:
金属材料
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GeSbTe薄膜
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内应力
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溅射功率
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退火温度
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高密度数据存储
李春林
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李宁
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颜家振
功能材料
doi:10.3969/j.issn.1001-9731.2014.07.023
将 Fe-16Cr-2．5Mo 合金在1100℃真空保温1 h 后分别炉冷,空冷和油冷,研究了热处理冷却方式对 Fe-16Cr-2．5Mo 合金阻尼性能的影响.分析了不同冷却方式所得合金的微观结构、内应力与阻尼性能之间的关系.结果表明,随冷却速度减小,对数衰减率峰值增大,峰值所对应的应变振幅减小.合金阻尼性能随冷却方式的变化可用 SB 内应力分布理论解释,保温后炉冷时,冷却速度较慢,晶粒较大,C 原子和部分置换原子容易沿晶界析出,且合金的空位浓度降低,致使内应力小于空冷和油冷,这是保温后炉冷阻尼性能最高的本质原因.
关键词:
Fe-16Cr-2. 5Mo合金
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阻尼性能
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冷却方式
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内应力
廖凯
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吴运新
材料科学与工艺
基于实验误差和模型误差，分析厚板应力测试不确定度产生的根源，确定每一种误差源的计算准则，并对误差源提取相应的厚板实验数据，对其不确定度进行计算。在获得总的应力测试的合成标准不确定度，对测试方法的误差进行分析。计算结果表明：层削法应力测试计算不确定度小于7 MPa，具有较高的测试精度。在模型误差和实验误差的综合作用下，层削法计算模型可以保持较高的准确性。
关键词:
不确定度
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铝合金厚板
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内应力
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层削法
周佑明
电镀与精饰
doi:10.3969/j.issn.1001-3849.2014.11.006
通过赫尔槽试验、偏转法、安时法等多种方法,测试了国内外市场上6种品牌硫酸镍所得镀镍层外观、内应力,镀液的电流效率、分散能力、整平能力及覆盖能力等性能,并进行对比.结果显示,金柯生产硫酸镍产生的针孔少于其它品牌,配制镀液无需预处理即可进行直接生产,其瓦特镍液获取镀层内应力最小,镀液分散能力、整平能力、覆盖能力和电流效率稍优于其它品牌硫酸镍.
关键词:
瓦特镍
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硫酸镍
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针孔
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内应力
毛小南
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周廉
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周义刚
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张鹏省
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于兰兰
稀有金属材料与工程
利用X射线衍射技术测试了TiC颗粒增强钛基复合材料Ti-6Al-4V+7%TiC(质量分数,下同)(T64), Ti-3Al-2.5V+7%TiC (T32)和Ti-6Al-2.5Sn-4Zr-0.5Mo-1Nb-0.45Si+3%TiC(T650) 的内应力.发现该复合材料在800℃左右存在一个应力性质转变点,即在800℃以上处理,钛基体感生残余拉应力,增强TiC颗粒感生残余压应力;在800℃以下处理,应力性质相反.并且内应力随处理温度升高而增加,由Eshelby 模型得出,该转变点和钛合金基体的相变点有关.
关键词:
内应力
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X射线衍射
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钛基复合材料
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TiC颗粒
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热处理
