H.W.Liu 1)
,
H.Ding 2) and J.Z.Cui 2) 1) School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China 2) School of Materials & Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
Porthole dies are important tools in extrusion process to produce hollow sections and the life of the dies counts for the cost of products. In this work, the finite element method was adopted to analyze a particular porthole die to produce hollow rectangle sections which are widely used in construction. The upper die was mainly studied. Because it is symmetrical, a quarter of the die was analyzed. The upper die was divided into 2199 elements with 3018 nodes. Elements were produced by four steps and the geometric shape of the die could be well simulated. The boundary condition was given according to the shape of the welding chamber and an empirical average extrusion stress was adopted, which was 210N/mm 2. Three-dimensional equivalent stresses were received. The original porthole die studied had obvious stress concentration and the stress distribution was very inhomogeneous, which would heavily affect the die life. A new design was proposed in which the portholes were rearranged and their shape and dimension were changed. According to the finite element analysis, the stress distribution of the improved die was quite homogeneous and the stress concentration was lessened.
关键词:
section extrusion
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null
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null
孙建春
,
盛光敏
,
陈登明
,
周安若
,
朱光俊
功能材料
1J50软磁合金的性能主要是通过H_2热处理获得的,在1130℃和H2气氛保护下对冷轧态1J50软磁合金进行了热处理.运用MATS-2010SA软磁测试仪对处理前后1J50软磁合金的磁性能进行了检测,运用金相显微镜、XRD等手段对处理前后1J50软磁合金的组织结构进行了分析.结果表明,通过H_2热处理,1J50软磁合金的矫顽力显著降低,起始磁导率和最大磁导率提高;组织结构发生明显变化,冷轧态1J50软磁合金组织为孪晶奥氏体,平均晶粒尺寸为200μm,处理过后,晶粒显著长大,平均晶粒尺寸为100μm;由于在600℃时采取了快冷,处理后1J50软磁合金中未出现大量FeNi相和FeNi_3相.
关键词:
H2热处理
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1J50
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组织结构
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性能
王亮
,
CAI Chun
应用化学
doi:10.3969/j.issn.1000-0518.2008.08.015
制备了高分子负载CuI催化剂,将其应用于1,3-偶极环加成反应.制备了1,2,3-三唑类化合物,考察了溶剂、碱、催化剂用量、反应气氛对反应的影响,确定了较佳的反应条件.研究表明,以PEG/H2O为溶剂在室温下就能有效地催化反应,生成单一的1,4取代的三唑化合物,同时,进一步考察了不同底物的反应效果.苄基和烯丙基类卤代烃活性较高.反应8 h得率为72%～94%;饱和卤代烃经延长反应时间有中等以上收率;芳烃反应活性较差,碘代芳烃在85℃反应24 h,只有中等收率,而溴苯根本不发生反应.催化剂经过简单的过滤洗涤后可重复使用4次.显示了较好的催化活性.
关键词:
高分子负载催化剂
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环加成反应
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三唑
杨松
,
宋宝安
,
李正名
,
廖仁安
,
刘刚
应用化学
doi:10.3969/j.issn.1000-0518.2002.03.013
合成了8个(Z)-2-(1H-咪唑-1-基)-1-(2,3,4-三甲氧基)苯乙酮肟脂(Ⅳ)新化合物,收率在62.1%～84.1%之间. 经元素分析、红外光谱、核磁共振氢谱表征了它们的结构,并讨论了化合物构型与光谱特征之间的关系.
关键词:
三甲氧基苯乙酮肟
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酯
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咪唑
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合成
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立体异构体
Liubing WANG
金属学报(英文版)
Tests under mechanical strain control were performed to investigate the TMF behavior of Z2CND18.12N within the temperature range between 150-550℃. Different strain amplitudes and phase-angles were applied. Total strain controlled low cycle fatigue test was also performed at the peak temperature of TMF cycling. The results show that the cyclic stress response of the material displayed an initial hardening regime followed by a saturation period and then cyclic softening till failure. The TMF cycling leads to the development of significant amounts of mean stress. Some life prediction models were employed to predict the TMF life of Z2CND18.12N, and the results indicate that the energy-based models provide good prediction on the thermal-mechanical fatigue behaviors of this material. An optical microscopic observation shows that the surface crack initiations and crack propagations are typically transgranular mode.
关键词:
Thermomechanical fatigue
陈玮
,
程继健
无机材料学报
doi:10.3321/j.issn:1000-324X.1999.01.004
为了探索新的透红外材料,本文研究了As2Se3-AsTe-CuI系统玻璃的形成区,制备了一系列不同AsTe和CuI含量的玻璃. 研究表明:该系统玻璃的形成范围相当大,As2Se3-AsTe二元系统可以任何比例形成玻璃,As2Se3-CuI和AsTe-CuI二元系统, 当CuI含量分别达70和40mol%时,仍可形成稳定的玻璃, 直径在20mm厚度在50mm以上的玻璃样品很容易得到. 研究了部分玻璃样品的远红外光谱,结果表明:该系统玻璃的结构单元主要是:[As(SeTe)3-xIx] (x=0～3)、[As2Te4]和[CuI4],随玻璃的成分不同,这些结构单元的相对比例也不同,根据研究结果提出了该系统玻璃的结构模型.
关键词:
硫系卤化物玻璃
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玻璃形成
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玻璃结构
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红外透射材料
陈玮
,
程继健
无机材料学报
为了探索新的透红外材料，本文研究了As2
Se3－AsTe－CuI系统玻璃的形成区，制备了一系列不同ASTe和CuI含量的玻璃．研究表明：该系统玻璃的形成范围相当大，AS2Se3－ASTe二元系统可以任何比例形成玻璃，AS2Se3－CuI和AsTe-CuI二元系统，当CSI含量分别达70和40mol％时，仍可形成稳定的玻璃，直径在20mm厚度在50mm以上的玻璃样品很容易得到．研究了部分玻璃样品的远红外光谱，结果表明：该系统玻璃的结构单元主要是：［AS（SeTe）3-xIx］（x＝0～3）、［As2Te4］和［CuI4］，随玻璃的成分不同，这些结构单元的相对比例也不同，根据研究结果提出了该系统玻璃的结构模型．
关键词:
硫系卤化物玻璃
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null
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null
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null
材料科学技术（英文）
The cyclic plastic straining electrode technique has been used to investigate the transient electrochemical behaviour of Fe-26Cr-1Mo stainless steel in 1M H2SO4 solution at a passive potential. The influence of plastic strain amplitude and plastic strain rate on the dissolution current response was analysed. The experimental results showed that the transient current was dependent on the competitive process of the surface film rupture and repassivation of the new surface. The high plastic strain amplitude and the high plastic strain rate caused a change of electrochemical activity of specimen surface. In the condition of low strain amplitude and strain rate:, the characteristics of current response was mainly relative to the process of new surface repassivation. The competition kinetics has been analysed through the comparison of plastic strain rate and repassivating rate.
关键词:
