热处理对14MnVTiRE钢4 mm薄板组织和力学性能的影响

14MnVTiRE钢[/%:0.10～0.15C、0.30～0.60Si、1.20～1.60Mn、0.03～0.09V、0.07～0.16Ti、0.10～0.15RE(加入量)]4 mm薄板的生产流程为180 t顶底复吹转炉-180 mm×1 260 mm连铸板坯-连轧-卷取工艺。在连铸时由结晶器喂φ2.5 mm RE丝。试验研究了950℃正火,950℃正火+690℃1～5 h回火对薄板组织和力学性能的影响。结果表明,正火后钢的组织为铁素体+细珠光体,在正火+690℃回火1～3 h钢中的珠光体片层碳化物发生球化,分布在晶界和晶粒内部,随回火时间进一步增加,碳化物呈点状和三角形,全部分布在晶界,材料的强度降低很大。14MnVTiRE钢薄板的最佳热处理工艺为950℃正火+690℃1～2 h回火,其屈服强度为510～610MPa,抗拉强度630～680 MPa,伸长率22%～25%。     

固溶处理对超级双相不锈钢S32750组织和性能的影响

研究了950～1 200℃60 min水冷的固溶处理对超级双相不锈钢S32750(/%:0.02C、0.49Si、1.03Mn、0.026S、0.001P、25.01 Cr、7.03Ni、3.80Mo、0.29N)12 mm板的组织、力学性能和耐蚀性的影响。结果表明,随固溶温度升高,钢中铁素体相增加,奥氏体相减少;在950℃加热时铁素体中析出大量σ-相,使钢的性能恶化,在1 050～1 100℃固溶处理后,钢中铁素体相和奥氏体相各占50%, S32750钢具有较好的综合力学性能和优良的耐蚀性能。     

实验室模拟控制轧制和调质处理对桥梁钢Q690q组织和性能的影响

研究了920℃精轧,830℃终轧以12℃/s冷至590℃,空冷的TMCP控制轧制工艺和TMCP+940℃淬火-630℃回火两工艺的桥梁钢Q690q(/%:0.05C、0.30Si、1.40Mn、1.10Cu、0.50Cr、0.80Ni、0.07V、0.55Mo,焊接冷裂纹敏感指数P_cm≤0.267)15mm板组织和力学性能。结果表明,TMCP工艺生产的桥梁钢Q690q组织主要由粒状贝氏体和少量铁素体组成,TMCP+调质处理后的组织为多边形铁素体和少量渗碳体,其屈服强度R_p0.2为845～870MPa,抗拉强度Rm895～900MPa,-20℃冲击功153～186J, -40℃为141～155 J。调质处理减小了钢材的M/A岛尺寸和位错密度,使Q690_q钢保持高强度的同时也具有较好的冲击韧性。     

Mussel-inspired strategy towards functionalized reduced graphene oxide-crosslinked polysulfone-based anion exchange membranes with enhanced properties

Chemical crosslinking is regard as an effective method to balance the ionic conductivity and dimensional stability of anion exchange membranes (AEMs). In this work, a series of crosslinked AEM composite membranes based on polydopamine-functionalized reduced graphene oxide (PDArGO) were constructed from quaternized polysulfone (QPSU) with amino groups via mussel-inspired chemistry strategy. On the one hand, as the dopant, the hydrogen bonding interaction between PDArGO and a large number of amino groups on the side chains of QPSU can enhance the water uptake of the membranes and has a positive influence on the ionic conductivity of composite membranes. On the other hand, PDArGO also acts as the crosslinker, which can form a micro-crosslinked structure with the amino groups on the side chains of the polymer through the Michael addition/schiff base reactions. Under the combined influence of the above two factors, the crosslinked composite AEMs exhibited special delightful properties. In general, the crosslinking reaction will lead to the decrease of the ionic conductivity of the membranes, but as for the membranes prepared by us, the ionic conductivity had been improved to some extent. Especially, the QPSU-1.5%-PDArGO exhibited 57% improvement in the hydroxide conductivity than that of pure QPSU membrane and reached the highest value of 61 mS cm^?1 at 80 °C. Besides, the crosslinked membranes also exhibited strong dimensional stability, good mechanical strength, comparable alkaline stability and improved methanol permeability.     

激光修复TC4钛合金显微组织与力学性能

本文以低氧TC4粉末为熔覆材料,采用激光修复技术制备了TC4钛合金面修复试样,对比研究了锻件和修复试样(沉积态)的显微组织和力学性能。结果显示修复试样的组织宏观上分为锻件基材区,热影响区和激光沉积区,三个区域中热影响区的显微硬度最高,沉积区和锻件基材的显微硬度相当。锻件试样的强度及塑性均略高于修复试样,同时发现40%修复试样(即拉伸试样承受载荷部位横截面上沉积区所占的面积分数为40%)的强度略低于50%修复试样,塑性则高于后者。表明采用低氧TC4粉末为熔覆材料时,有利于修复试样沉积区和基材区强度和塑性的匹配,从而提高修复试样的综合性能。对拉伸断口进行扫描电镜观察发现,锻件试样拉伸失效后断口呈现出典型的韧性断裂特征,而修复试样的断口则表现复杂,从沉积区到锻件基材区呈现出解理台阶到韧窝的连续变化特征,同时断口形貌与显微组织呈现出很好的对应关系。     

石墨烯强化CuCr25合金的制备与性能

采用高压低温SPS烧结的新工艺制备了高硬度高电导率的CuCr25/石墨烯复合材料。X射线衍射(XRD)和拉曼分析(Raman)揭示石墨烯在新合金的制备过程中并未变性亦无新相产生,利用扫描电镜(SEM)以及能谱仪(EDS)进行形貌分析显示石墨烯在新合金中分散均匀。性能测试结果显示,在600℃,300 MPa条件下经SPS烧结后制得的CuCr25/石墨烯合金,与对比试验中采用相同工艺制得的未添加石墨烯的CuCr25合金相比,硬度提高了11.3%,电导率下降了4.2%;而与传统工艺制备的CuCr25合金相比,其电导率和硬度则分别提高了35%和48%,表明成分和工艺的改进对性能的提高均有贡献。     

杯芳烃磺酸的应用新进展

简要介绍了两类水溶性杯芳烃---磺化杯芳烃以及磺化硫代杯芳烃的合成,合成过程虽经多步处理,但合成方案较成熟,处理过程简单;其次概述了磺化杯芳烃的热稳定性,该性质为后续的应用研究提供了很好的基础条件,并着重综述了磺化杯芳烃在催化方面的应用,其较强的酸性基团满足了催化反应中所需的酸性条件,此外,与其他类型的酸催化剂相比,磺化杯芳烃易于从反应混合物中分离回收再利用,是一种绿色有机催化剂;最后在配位作用、络合包结、分子离子的识别等作用中作为母体化合物,其应用性能表现良好。     

Magnetic,Dielectric and Complex Impedance Properties of xBa_(0.95)Sr_(0.05)TiO_3–(1-x)BiFe_(0.9)Gd_(0.1)O_3Multiferroic Ceramics

xBa_(0.95)Sr_(0.05)TiO_3–(1-x)BiFe_(0.9)Gd_(0.1)O_3[x BST–(1-x)BFGO](x = 0.00, 0.10, 0.20 and 0.25) multiferroic ceramics were prepared by the standard solid-state reaction technique. Structural characterization was performed by X-ray diffraction. All the samples showed rhombohedral distorted perovskite structure. Surface morphology of the ceramics was studied by the field emission scanning electron microscope(FESEM). From the FESEM observation, the grain size was observed to be decreased with increasing BST content. Enhanced magnetic properties were observed in BFGO with the increase in BST content because of large lattice distortion. The complex initial permeability increased with the increasing of BST content. The study of dielectric properties showed that the dielectric constant increased, whereas dielectric loss decreased with increasing of BST content due to the reduction of oxygen vacancies. An analysis of the electric impedance and modulus with frequency was performed at different temperatures. Non-Debye-type relaxation processes occur in the compound which was confirmed from the nature of the Cole–Cole plot. The DC conductivity was found to increase with the rise in temperature which indicates the semiconducting behavior of the compound with characteristics of the negative temperature coefficient of resistance. The activation energy, responsible for the relaxation determined from the modulus spectra(0.246 eV), was found to be almost same as the value obtained from the impedance study(0.240 eV), indicating that charge carriers overcome the same energy barrier during relaxation. The frequency response of imaginary parts of electric impedance and modulus suggested that the relaxation in xB ST–(1-x)BFGO ceramics follows the same mechanism at various temperatures.     

H13钢激光熔覆Co基涂层工艺优化及组织性能

采用Nd:YAG激光器在H13钢表面制备Co基合金涂层,分析扫描速度和电流强度对涂层成形质量的影响,确定最优参数。借助扫描电镜和X射线衍射仪分析了涂层组织形貌及物相组成。使用显微硬度计和摩擦磨损试验机测试了涂层截面硬度及耐磨性能。结果表明：激光熔覆扫描速度增加和电流强度降低,均可使Co基合金涂层熔高和熔宽降低,孔洞和裂纹数量减少。优化工艺参数为：扫描速度120 mm/min,电流200 A。该工艺制备涂层组织主要由细小的枝晶和共晶组成,包括γ-Co和M23C6相,涂层硬度达到610 HV0.2;耐磨性是淬火回火态H13钢的1.32倍。     

Alternative for Rapid Detection and Screening of Pork,Chicken, and Beef Using Dielectric Properties in the Frequency of 0.5 to 50 GHz

Dielectric property at high microwave frequency region has been utilized for possible rapid detection and screening of different types of meat, especially for halal authentication. This investigation focused on both raw and sterilized (processed) beef, pork, and chicken samples. Dielectric response that consists of dielectric constant and dielectric loss factor was measured over the range of 0.5 to 50 GHz. All raw and sterilized meat samples could be differentiated by the dielectric values. Two distinct peaks were observed only for both raw and sterilized pork samples at the frequency around 7.43 and 31.19 GHz. These peaks can potentially be linked to compounds that exist only in pork such as DNA, microbes, enzyme, proteins, amino acids, and many others. Dielectric values for sterilized samples were lower than raw samples due to molecule structural changes that occurred in the samples. The dielectric results promise a great potential of utilizing dielectric properties as a rapid on-site detection approach prior to subsequent laborious analysis.