热轧带钢力学性能预测模型及其应用

为实现对热轧带钢的屈服强度、抗拉强度、断裂延伸率等力学性能的预测及控制,利用人工神经网络技术,分别建立了根据生产工艺参数预测力学性能的质量模型,以及根据力学性能要求对生产工艺参数进行优化的逆质量控制模型.利用质量预测模型,分析得出屈服强度随卷取温度的上升而下降的变化规律,进而可以对组织性能进行在线调整,实现在线应用.     

原位生成CeB_6/B_4C陶瓷的力学性能和显微组织

通过B4C、CeO2和C的化学反应,采用原位生成法,在热压烧结的条件下制备了CeB6/B4C陶瓷材料.研究了CeB6/B4C陶瓷材料的力学性能和显微组织,并对其增韧机理进行了分析.结果表明:原位生成的CeB6/B4C陶瓷只有CeB6和B4C两相,其显微维氏硬度、抗弯强度、断裂韧性最大值分别达到40.64GPa、346.7MPa、5.95MPa·m1/2,比纯碳化硼分别提高了52.50%、17.96%、61.68%.原位生成的CeB6颗粒细晶增韧补强,B4C和CeB6颗粒之间热膨胀系数不匹配产生的残余应力导致的裂纹偏转以及沿晶断裂是CeB6/B4C陶瓷的主要增韧机制.     

机械合金化合成TiB2/Fe3Al纳米复合粉体

采用铁、铝、钛、硼四元粉体机械合金化与后续热处理的方法合成纳米TiB_2／Fe_3Al复合粉体,并利用XRD、DSC、SEM和TEM等对粉体进行了表征。结果表明：在球磨过程中,四元粉体形成了Fe(Al,Ti,B)过饱和固溶体,有序度不断降低,逐渐向非晶态转变,同时粉体晶粒尺寸逐渐细化,球磨40h后Fe(Al,Ti,B)的晶粒尺寸为9．6nm;并在热处理过程中Fe(Al,Ti,B)分解生成纳米Fe_3Al和TiB_2复合粉体,同时发生组成相晶粒生长,结构有序度提高等转变。     

Effects of Sedentarism and Treadmill Training in Mechanical Properties of Muscles of Ovariectomized Rats with High-Fat Diet

The aim of this study is to evaluate the ability of physical training in the maintenance of muscle strength in rats with HFD （high-fat diet） after OVX （ovariectomy）. Eighty Wistar rats are at eight weeks of age and weight 200 g which divided into 8 groups （n = 10） and treated for 12 weeks： GA： OVX ＋ ND （normal diet）, GB： OVX ＋ ND ＋ training, GC： sham ＋ ND, GD： sham ＋ ND ＋ training, GE： OVX ＋ HFD, GF： OVX ＋ HFD ＋ training, GG： sham ＋ HFD and GH： sham ＋ HFD ＋ training. HFD consists of standard ration for rats with addition of 30% lipids. In training groups, physical training five training/week was conducted on a treadmill with adaptation period of three weeks up to 18 m/s for one hour, training were performed for 12 weeks. The sedentary animals remained in individual box. To analyze the effects of training and diet, tensile strength tests of the gastrocnemius muscles were conducted： the speed of 0.1 mm/min. Analysis of variance was performed to compare groups. The mean （SD） obtained for the maximum load （N） were： GA 57.77 （6.89）, GB 62.74 （5.07）, GC 49.45 （6.06）, GD 59.42 （5.26） and GE 55.58 （4.72）, GF 62.50 （4.56）, GG 58.35 （4.54） and GH 56.67 （5.87）, respectively. There were no differences for maximum load between surgeries （p = 0.004） and between treatments （p = 0.000）. Differences were found also for the relationship surgery diet treatment （p = 0.007）. For the variable stiffness （N/mm）, there were not statistically significant differences： GA 5.03 （0.72）, GB 5.08 （1.09）, GC 5.17 （0.53）, GD 5.35 （0.80）, GE 5.52 （1.20）, GF 5.36 （1.07）, GG 4.83 （1.03） and GH 5.40 （0.73）. For the toughness （N/mm）, there were differences between treatments （p = 0.010） and the ratio diet treatment （p = 0.024）： GA 455.00 （107.21）, GB 541.96 （126.80）, GC 394.97 （84.67）, GD 566.90 （157.07）; GE 424.63 （113.03）, GF 478.07 （106.03）; GG 517.44 （98.65?     

基于Linux的真空断路器机械特性测试仪的设计

真空断路器的可靠性,主要依赖于其机械特性的可靠性,而这需要有相应的测试设备来对其状态进行检测,便于工作人员对其进行维护.真空断路器机械特性测试仪是以嵌入式Linux为平台构建的嵌入式操作系统,运用Qt/E编写了界面美观、人机交互性能良好的操作控制图形用户界面程序,运用MySQL数据库编写相应的程序模块实现检测结果的存储、查询和传输,达到高精度、高性能、操作简便实现真空断路器机械特性参数测试的目的.     

自蔓延—离心法制备的不锈钢内衬复合钢管的力学性能

研究了自蔓延－离心法制备的不锈钢内衬（Ｃｒ１３－１４,Ｎｉ１４－１６）复合钢管不锈钢层的力学性能及热膨胀性能。用扫描电研究了拉伸试样的断口形貌,用透射电镜研究了不锈钢层的组织结构。研究表明,不锈钢内衬与基体碳钢之间热膨胀系数相差较大。不锈钢内衬主要由柱状晶组成,柱状晶为奥氏体,柱状晶间有一薄层铁素体,铁素体区有ＡｌＮｉ金属间化合物析出相,在奥氏体和铁素体有相界有α相析出。     

Cr_(80)Al_(20)机械合金化的试验研究

通过 X射线衍射、SEM分析及显微硬度测试等手段 ,研究了 Cr80 Al2 0 混合粉末机械合金化过程中的组织、相结构及硬度等的变化。结果表明 ,Cr80 Al2 0 混合物粉未经 96 h机械合金化后 ,其组织为 Cr(Al)的过饱和固溶体加上η - Al Cr2 金属间化合物     

机械式双金属复合管焊接质量控制

探讨采用封焊形式的机械式双金属复合管的焊接质量控制。要点在于制管质量控制、封焊及施工过程的控制。并建议采用管端堆焊的形式解决机械式复合管的焊接根本难题。     

Optimising the T6 heat treatment for gravity cast AlSi7MgCu0.5 alloy V8 cylinder heads

Alternatives to the Standard T6 heat treatment that relied on a 5-h solution heat treatment at 490 °C were investigated in effort to reduce the heat treatment cycle time for the manufacture of AlSi7MgCu0.5 alloy V8 cylinder heads without sacrificing the mechanical properties while providing extra capacity in the heat treatment plant. The optimum T6 heat treatment process was identified to be a SHT at 545 °C for 1 h followed by ageing treatment at 180 °C for 3 h. Mechanical properties of the cylinder heads thus manufactured were markedly superior while the total heat treatment duration was reduced by 2.5 h with respect to the Standard heat treatment. This implied a capacity increase of %61 and rendered the undertaking of a major customer order possible.