TG.Nieh(Lawrence Livermore National Laboratory
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P.O.Box 808
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L-350
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Livermore
,
CA 94551
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USA )
材料科学技术（英文）
Intermetallic beryllides are potential light-weight, high-temperature structural materials. In this paper. the processing techniques, microstructure. deformation, and oxidation properties of intermetallic beryllides are described. In addition to nickel beryllides (NiBe). which is treated as a model system.other high beryllium-containing refractory beryllides, such as Nb2 Be17. VBe12. are also studied.The room temperature deformation and high-temperature creep properties of these beryllides are repor4ed. At room temperature. NiBe exhibits certain tensile ductility (~ 1 .3%). but all other beryllides are essentially brittle. Nonetheless, these beryllides become ductile at temperatures above approximately 1000℃. Their creep properties are presented. The creep properties are compared with those of intermetallic aluminides. Also. a comparison is made between the ductile-to-brittle transition behaviour of intermetallic beryllides and that of aluminides. Although beryllides are generally oxidation resistant at high temperatures, some beryllides, e.g., ZrBe13, suffer the pest reaction during oxidation at intermediate tem peratures. The pest mechanisms are proposed
关键词:
申文竹
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李春福
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王朋飞
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陈功剑
材料热处理学报
通过高温试验装置在模拟井下工况温度25～350℃范围内进行了316L不锈钢的拉伸试验。结合拉伸试验数据、拉伸后微观结构以及断口形貌对316L不锈钢的25～350℃范围内的拉伸变形行为进行了探讨。应用温加工变形理论,建立了316L不锈钢在井下温度场环境中的形变本构方程。基于拉伸试验数据,计算了应变速率因子Z,变形激活能Q,建立了316L不锈钢温变形过程的流变应力计算模型,为完井设计中膨胀管膨胀施工提供了参考依据。
关键词:
316L不锈钢
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拉伸行为
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动态应变时效
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流变应力
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本构方程
朱静
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李荣
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张丽萍
金属学报
<正> 18Ni(350)马氏体时效钢是在18Ni(250)马氏体时效钢的基础上提高Co,Ti含量而形成的。对18Ni(250)钢的组织结构已经进行了较为系统的研究。提高Co,Ti含量使18Ni(350)钢时效后的强度明显高于18Ni(250)钢。关于18Ni(350)马氏体时效钢时效强化相的研究,已有很多报道,本文从时效结构的观察和分析入手,探讨18Ni(350)的强化机理并提出了合适的时效热处理制度。 试验用钢的化学成分(Wt-％)为:C0.007,Si0.005,Mn0.01,S0.005,P0.004,Co12.17,Ni17.99,Mo4.90,Ti1.31,A10.10,Fe余量。经双真空冶炼的钢锭,在
关键词:
M.L. Huang
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H.X. Li
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H. Ding
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Y.P.Ren
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S.M. Hao
金属学报(英文版)
Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy (SEM), electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA-EDS), and X-ray diffraction (XRD) have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4at.pct and the Zn content is 8at. pct-48 at.pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm,b=1.121-1.142nm, c=0.950-0.977 nm.
关键词:
Mg-Zn-La system
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null
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null
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null
魏立群
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陆济民
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严家高
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沈汉昌
上海金属
doi:10.3969/j.issn.1001-7208.2002.02.011
根据φ180/φ400×320及V100/V300×350四辊轧机的设备特点和产品情况,研究开发了能自动适应轧件宽度变化的变接触长度支承辊辊型曲线,以提高轧机的板型控制能力,使冷轧带钢的横向同板差下降约45%,轧制厚度精度提高40%,边裂现象明显减少,并有效防止支承辊辊面剥落,取得明显实效.
关键词:
冷带轧机
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支承辊
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变接触长度辊型
WAN Wen-juan
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HAN Guang-wei
钢铁研究学报(英文版)
The microstructure of hot-rolled AEREX350 alloy under various heat treatments was investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is found that with increasing temperature, η phase precipitated firstly at grain boundaries in parallel at 800℃ and then began precipitating within grains at about 980℃. The η phase precipitating at grain boundaries played a role on preventing the migration of grain boundaries, and that precipitating within grains would develop as Widmanstätten structure with further increasing temperature. Both η phase dissolved at the temperature between 1085℃ and 1095℃, resulting in grain growth promptly due to release of pinning effect on grain boundaries. γ′ phase precipitated during the process of air cooling after hot-roll, and dissolved at temperature between 1010℃ and 1020℃.
关键词:
heat treatment;microstructure;precipitate;AEREX350
陈伟东
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王建伟
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王力军
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卢世刚
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陈松
稀有金属
doi:10.3969/j.issn.0258-7076.2008.01.013
通过恒温氧化实验研究了氢化锆在350～600℃纯氧中的氧化行为,分析了温度和时间对氧化层质量增重的影响规律,并借助Ⅺm,SEM等分析测试手段对氧化层的物相组成和截面形貌进行分析.结果表明,氢化锆的质量增重随着氧化温度的升高而增大,450℃以下,氧化反应速度很慢;500'～600℃温度范围内,氢化锆的质量增重与氧化时间的关系曲线符合抛物线规律.氧化层由内到外分为致密层和疏松层,氧化层主要由单斜相M-zeO2组成.
关键词:
氢化锆
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恒温氧化
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氧化层
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ZrO2
任玉平
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李俊杰
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李松
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肖娜
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孙世能
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秦高梧
中国有色金属学报
采用合金法,利用X射线衍射、扫描电镜及能谱成分分析等手段测定Mg-Zn-Al合金350℃时的相平衡关系及其成分,建立富镁角350℃等温截面.结果表明:α-Mg固溶体与L、φ、γ三相保持相平衡关系,不存在以前普遍认为的τ与α-Mg 的相平衡.获得350℃时φ相成分范围,即53.5%~57.2%Mg、17.7%~30.7%Zn 和15.8%~27.7%Al(摩尔分数).Zn和Al两种元素可以同时固溶于α-Mg相中.但Al的加入提高了Zn在α-Mg中的溶解度,当α-Mg和L相平衡时,溶解度最大可达3.9%,远大于Mg-Zn二元系的2.1%.而当α-Mg与γ相平衡时,Zn的加入降低Al在α-Mg中的溶解度,即由Mg-Al二元系的7.8%降至5.2%.Al在Mg-Zn二元金属间化合物中的固溶度较大,可达7.7%,从而使其热稳定性得到提高.
关键词:
Mg-Zn-Al三元系
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相平衡
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平衡合金法
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固溶度
张朋
,
周立正
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包建文
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钟翔屿
,
刘刚
,
陈祥宝
复合材料学报
以苯乙炔苯酐(4-PEPA)为封端剂,异构联苯四甲酸二酐(α-BPDA)作为二酐单体,通过选择合适的二胺单体及优化配比,研制了耐温等级高于350℃,适用于RTM工艺的聚酰亚胺基体树脂HT-350RTM,选用U3160单向碳纤维织物作为增强体,采用RTM工艺制备了HT-350RTM树脂基复合材料层合板(U3160/HT-350RTM).结果表明:HT-350RTM树脂最低黏度可达390mPa·s,在280℃下保持黏度低于1Pa·s的时间大于2h,能够满足RTM工艺的要求.经过高温固化后,HT-350RTM树脂的玻璃化转变温度为392℃,热分解温度(分解5％)高达537℃.采用RTM工艺制备的U3160/HT-350RTM复合材料层合板孔隙率仅为0.34％,室温下具有良好的基本力学性能,315℃和350℃下的力学性能保持率均高于60％,能够满足350℃工况下的长期使用要求.
关键词:
RTM
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聚酰亚胺
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复合材料
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力学性能
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耐热性能
