W.Huang
,
X.Nie
,
X.Zan
,
Y.M.Xia
金属学报(英文版)
A new experimental technique has been developed for the performance of high temperature, high-strain rate tensile experiments in the self-designed tensile impact apparatus. This technique uses rapid contact heating method to heat the specimen to the desired temperature, thus avoids a significant temperature rise in incident and transmitted bars, and at the same time it is capable of retaining a nearly homogeneous temperature field within the specimen. As an illustration of its application, the hightemperature response of the forging die steel 5CrMnMo at high strain rates has been examined. Stress-strain curves are obtained for this material at strain rates ranging from 230s^-1 to 1200s^-1 and at temperature ranging from 25 to 606PC, respectively. For comparison, quasi-static experiments are performed over a slightly smaller range of temperatures.
关键词:
elevated temperature
,
null
,
null
Y.Q.Wu
金属学报(英文版)
The hot deformation of an Al-Cu-Mg alloy was studied in the two temperature ranges (room temperature-300℃ and 400℃-480℃). The rate-independent flow curves are typical of elasto-plastic response with significant work hardening followed by strain softening below 300℃. Similar dislocation structures with high density tangled into grain interiors were observed by TEM, which suggests that the process of obstacles arresting mobile dislocations results in this macroscopically rate-independence. At 400-480℃, all rate dependent flow behaviors characterized by a continuous softening after an initial work hardening at a small plastic strain show large tensile elongations. Long dislocation segments around the second phases infer their good mobility to climb across obstacles. Grain boundary morphology observed by TEM suggests that the capacity of the grain boundaries to absorb the dislocations sensitively accounts for the rate-dependent mechanical properties.
关键词:
rate dependence
,
null
,
null
G.Z.Kang
,
Q.Gao
,
J.Zhang
金属学报(英文版)
Based on the experimental results of the ratcheting for SS304 stainless steel, a new visco-plastic cyclic constitutive model was established to describe the uniaxial and multiaxial ratcheting of the material at room and elevated temperatures within the framework of unified visco-plasticity. In the model, the temperature dependence of the ratcheting was emphasized, and the dynamic strain aging occurred in the temperature range of 400-600℃ for the material was taken into account particularly. Finally, the prediction capability of the developed model was checked by comparing to the corresponding experimental results.
关键词:
constitutive model
,
null
,
null
任韦波
,
许金余
,
白二雷
,
苏灏扬
材料热处理学报
以矿渣和粉煤灰为原料,制备了陶瓷纤维增强地质聚合物混凝土(CFRGC).通过抗压强度试验、超声波测试和裂缝宽度检测,引入小波变换理论,研究了不同温度、不同纤维掺量下CFRGC强度、波速、频谱特征的变化规律以及温度裂缝的开展演化情况.结果表明,高温后CFRGC内部结构受损,导致抗压强度降低,纵波波速和声阻抗减小,温度裂缝宽度增大;声波测试信号经小波分解后在各频段内的功率谱密度分布及能量随损伤的增大有较为明显的变化,某一频段内的信号能量对损伤比波速更敏感;纤维体积掺量为0.3％时,陶瓷纤维对地质聚合物混凝土的高温性能具有良好的改善效果.
关键词:
地质聚合物混凝土
,
陶瓷纤维
,
高温
,
超声波检测
,
小波变换
宋海申
,
赖延清
,
李劼
,
刘业翔
,
张治安
功能材料
doi:10.3969/j.issn.1001-9731.2013.19.024
分别以 LiPF6、LiBOB 和 LiPF6/LiBOB 混合盐为电解质,研究了不同电解液对 LiFePO4/石墨动力电池高温循环性能的影响。结果表明,LiBOB 盐抑制了正极溶铁行为,并提高了正极高温循环充放电效率；由于 LiBOB基电解液对正极的保护及在负极表面良好的成膜作用,使得LiFePO4/石墨电池高温循环性能得到明显改善,但是增大了电池阻抗。LiPF6/Li-BOB混合盐可以发挥 LiBOB盐的优点增加正极稳定性,在石墨表面形成致密的 SEI 膜并能够有效改善电池高温循环性能,同时避免了单纯使用 LiBOB盐时阻抗较高的缺点。使用 LiPF6/LiBOB 混合盐,利用LiPF6盐低阻抗特性及 LiBOB盐对正、负电极的保护作用,可以有效提高电池电化学性能。
关键词:
动力电池
,
LiBOB
,
混合盐
,
LiFePO4
,
循环
,
高温
彭建强
,
闫红博
,
孙福民
,
宗影影
,
单德彬
材料科学与工艺
为了掌握含Re的高温叶片用钢11Cr10Co2W2MoReVNbNB的最佳热处理工艺和组织性能,对钢进行了热处理工艺试验和组织性能分析.采用Gleeble3800型热/力模拟试验机测定了钢的相变点,采用IN-STRON-5582型电子拉力试验机、HVS-1000型维氏硬度计测定了钢的力学性能,采用Olympus-PMG3型光学显微镜、SUPRA55型扫描电镜、FEI Tecnai G2 F30型透射电镜分析了钢的组织性能.实验结果表明:钢在1 100～1 140℃内淬火、在660～ 700℃内回火时,淬火温度和回火温度对材料性能基本没有影响；与其他高温用12％ Cr钢相比,11 Cr10Co2W2MoReVNbNB钢具有良好的韧性,室温V型冲击性能高达40 J以上；钢的组织为回火索氏体,组织均匀、晶粒细小.钢的最佳热处理工艺为(1 120±10)℃油冷+(690±10)℃空冷,钢的主要强化相为M23 C6,Re主要存在于基体中,起固溶强化作用.
关键词:
含Re叶片钢
,
汽轮机
,
热处理工艺
,
高温
,
组织
左建华
,
岳明
,
王云桥
,
路青梅
,
刘燕琴
,
张东涛
,
刘卫强
,
张久兴
,
郭朝晖
稀有金属
采用X射线衍射分析(XRD)和磁性能测试等方法,分析了Tm元素掺杂对SmCo5晶体结构和内禀磁性能的影响.XRD测试结果表明:SmCo5和Sm0.8Tm0.2Co5.2均为CaCu5结构,掺杂Tm元素后,晶格常数c值增大,而a,b与晶胞体积减小;M-T曲线测试结果表明:SmCo5和Sm0.8Tm0.2Co5.2的居里温度分别为957和965 K;在测试外加场为7T的条件下,300 K时SmCo5的各向异性场HA和饱和磁化强度M7T均高于Sm0.8Tm0.2Co5.2;当温度升高至473 K,SmCo5的HA和M7T要低于Sm0.8Tm0.2Co5.2,说明SmCo5中进行Tm元素掺杂可以有效的改善其在高温条件下的磁性能.
关键词:
SmCo5
,
Tm元素掺杂
,
晶体结构
,
高温
,
内禀磁性能
刘庆
,
赵铁军
,
刘志强
,
曹承伟
硅酸盐通报
建筑结构中的混凝土材料在遇到火灾时,往往会暴露在高温的作用下,而高温作用后混凝土的相关性能对建筑物的使用安全性至关重要.本文介绍了高温对混凝土的物理性能和力学性能的影响.混凝土试块会经过相对较低温度(小于300℃)和相对高的温度作用,并通过不同的冷却方式后得到混凝土试块的抗压强度.高温作用后混凝土的抗压强度会严重劣化,混凝土的剩余强度也随着冷却制度的不同而不同.随着温度的升高,混凝土的断裂能逐渐降低.且高温作用后混凝土抗毛细吸水性能严重劣化,喷水冷却后混凝土的毛细吸水能力显著增大.
关键词:
高温作用
,
剩余强度
,
断裂能
,
耐久性
都凡
,
欧阳利军
,
陆洲导
,
陈有亮
,
镇斌
玻璃钢/复合材料
钢筋锈蚀是导致钢筋混凝土结构耐久性降低的重要原因.FRP筋具有轻质、高强和耐腐蚀等优异特性,因而有望成为传统钢筋的补充材料.FRP筋混凝土构件在服役过程中会受到高温(火灾)环境的威胁,因而FRP筋及FRP筋混凝土构件在高温(火灾)作用下的力学性能是其应用于实际工程时所面临的重要课题.综述了国内外FRP筋及FRP筋混凝土构件高温力学性能的研究成果,包括FRP筋的高温力学性能、高温对FRP筋-混凝土粘结强度的影响及FRP筋混凝土构件抗火设计方法,并对相关文献的试验数据与理论成果进行了分析和总结,指出了未来需进一步研究的方向.
关键词:
FRP筋
,
混凝土
,
高温
