镍基粉末冶金FGH95高温合金的拉伸及低周疲劳性能研究

在420～650℃的温度范围内,研究了PM FGH95高温合金在应变率0.0001～0.01 s-1范围内的拉伸性能及在不同应力比R=-1及R=0下的低周疲劳性能.拉伸试验结果表明:在此温度范围内,应变率对弹性模量、拉伸屈服强度及塑性模量的影响可以忽略不计;并且应变率自0.0001 s-1增大至0.01 s-1时,弹性模量、拉伸屈服强度及塑性模量受温度的影响也不明显.PM FGH95合金受材料微结构的影响很大,材料含有的微缺陷对其力学性能有非常不利的影响.LCF试验结果表明:PM FGH95合金是循环硬化材料.当应力比R=-1时,温度对LCF寿命的影响很小;但在应力比R=0时,LCF寿命受温度的影响很大,且随着温度的增加材料的低周疲劳寿命减小.SEM断口扫描发现,断裂表面有很多的解理面,但没有疲劳条带,且此断裂模式下没有明显的塑性变形,所以FGH95合金的低周疲劳寿命几乎是由裂纹萌生阶段决定的.     

氧化钨纳米颗粒和纳米线的选择合成及光致发光研究

采用无机盐辅助水热法选择调控合成了WO3纳米颗粒和纳米线.通过SEM,TEM,EDX和XRD等手段对产物进行了表征.研究了形貌和尺寸对WO3的光致发光性能的影响,并探讨了形貌和尺寸对WO3光致发光性能影响的机制.     

Johnson-Cook dynamic constitutive relationship for TC 16 titanium alloy

The true stress--strain curves of TC16 alloy with a wide range of strain rates were investigated under uniaxial quasi-static tension and uniaxial dynamic compression with the lnstron 8032 test machine and the split Hopkinson bar respectively. The results indicate that the true stress increases with increasing strain rate, while decreases with increasing temperature. Under the 105 s^-1 high strain rate and temperature higher than 673 K, the true stress would even be less than that under quasi-static condition. A new method incorporating TCl6＇s stress strain curve developing item was proposed to determine the coefficients in J-C model easily and to avoid the estimation of the adiabatic temperature rising. The Johnson-Cook dynamic constitutive relationship for TC16 was obtained for the first time. Good agreement was obtained between the model prediction and the experimental stress--strain curves for TC16 under both quasi-static and dynamic loadings.     

La1-xSrxCo1-yFeyO3材料制备及结构分析

以溶胶-凝胶法制备La1-xSrxCo1-yFeyO3粉体,对粉体在不同温度热处理后的晶体结构进行XRD表征,详细研究粉体的成分组成以及发生的结构转变.结果表明,凝胶前驱体粉体颗粒比表面增大有利于钙钛矿结构晶相形成;合成粉体受前驱体比表面程度影响形成两种具有不同空间群钙钛矿结构晶相,并且各晶相元素化学计量比不相同,两相体系较稳定.     

吡咯对电沉积磷酸钙类复合涂层的生长方式的影响

利用电化学沉积的方法,在电解液中加入吡咯,制备了磷酸钙-聚吡咯复合涂层.结果表明:吡咯使涂层的生长方式发生了改变.未加入吡咯获得的单一的磷酸钙沉积陶瓷膜呈现无序排列,叶片状.电解液中加入吡咯后,陶瓷膜层有序排列,呈针状且整个膜层的晶粒增大.红外光谱分析表明,出现了C=C和N-H基团的伸缩振动吸收峰,说明吡咯已经由电解液中转移到涂层中.相分析表明:吡咯的加入并没有改变涂层的相组成,说明整个过程中仅有少量的吡咯进入涂层.     

Evolution of {001 } （110） orientation and related lattice rotation of A1 alloy 6111 during rolling

The texture evolution and lattice rotation in A1 alloy 6111 with an initial {001} （110）component during symmetrical and asymmetrical roiling were investigated by means of orientation distribution function（ODF）. The results show that the as-rolled initial {001 } （110） orientation evolves into not only the copper orientation but also all the other orientations along the β fiber, including the brass orientation, by lattice rotation around special directions. Compared with the symmetrical rolling, the {001 } （110）component in the surface layer on the slower roller side evolves more quickly into the orientations along the β fiber during asymmetrical rolling, while that in the surface layer on the faster roller side evolves more slowly.     

Investigation on gradient material fabrication with electron beam melting based on scanning track control

A new electron beam control system was developed in a general vacuum electron beam machine by assembling with industrial control computer, programmable logic control （PLC）, deflection coil, data acquisition card, power amplifier, etc. In this control system, scanning track and energy distribution of electron beam could be edited off-line, real-time adjusted and controlled on-line. Ti-Mo gradient material （GM） with high temperature resistant was fabricated using the technology of electron beam melting. The melting processes include three steps, such as preheating, melting, and homogenizing. The results show that the GM prepared by melting technology has fine appearance, and it has good integrated interface with the Ti alloy. Mo and Ti elements are gradually distributed in the inter.face of the gradient material. The microstructure close to the Ti alloy base metal is α ＋ β basket-waver grain, and the microstructure close to the GM is a single phase of β solid solution.     

关于输气管线内衬聚乙烯管可防止其腐蚀的商榷

本文参照德国一实例，即利用多种类型PE衬层，在一定温差及有气体扩散阻挡层和无气体扩散阻挡层的条件下，详细地叙述了高压酸性气体对其进行长期渗透作用的试验。结果显示：水蒸气和腐蚀性气体（如H2S）的渗透作用是不能忽视的，甚至当PE层为5mm时亦有一定渗透性；此外，在衬层底部尚产生了化学腐蚀作用，从而促使人们必须考虑须正确选择PE下边的防腐底层。     

Cu-Ag合金强度与弹性模量在组织纤维化过程中的变化

采用冷拉拔制备了Cu-6％Ag及Cu-12％Ag纤维相复合强化合金线材，研究了组织纤维化对Cu—Ag合金强度与弹性模量的影响。随变形程度的增加，合金抗拉强度和弹性模量在明显升高后趋于饱和。Cu-12％Ag合金比Cu-6％Ag合金有更高的应变硬化速率和抗拉强度。在较低变形程度范围内，Cu-6％Ag合金的弹性模量高于Cu-12％Ag合金。在较高变形程度范围内，Cu-6％Ag合金的弹性模量低于Cu-12％Ag合金。纤维化组织中的高密度晶体缺陷使得两种Ag含量的合金弹性模量均低于理论预测值。合金的强度和弹性模量主要取决于共晶体数量、相界面密度、变形抗力及两相之间的变形协调行为。     

隧道式热风循环电热干燥炉及其应用

本文介绍了一种干燥效率高、节能降耗、温差小、干燥产品质量高的隧道式热风循环电热干燥炉.该炉采用多点分区控温,各均温区为一个热风循环组元,实现炉内双侧纵横双向热风循环,热风循环组元根据干燥传热学按干燥第一阶段、第二阶段在干燥炉长度方向间距不同布置.可根据产品规格和工艺需要,实现严格的温度曲线,同时也便于调整.热风循环装置应用于隧道式干燥炉,能强化对流换热,均匀炉温,提高干燥质量.推广应用结果表明:本炉型非常适合于规模化生产高质量树脂磨具,比箱式炉可节能约40%.