1α-羟基去氢表雄酮的合成与应用研究进展

1α-羟基去氢表雄酮是合成马沙骨化醇的起始原料,也是合成维生素D类衍生物关键中间体和原料,具有良好的市场前景。标题化合物的合成研究已有半个多世纪的历史,但适于工业化的合成工艺尚待于开发。按起始原料不同对标题化合物合成方法和应用进行综述。合成标题化合物起始原料主要有1,4-雄烯二酮和去氢表雄酮。以去氢表雄酮为原料的合成方法又分为化学法和微生物法。     

热处理对Mg-3Sn-1Mn镁合金组织和性能的影响

通过光学和电子显微镜、XRD分析以及抗拉和蠕变测试,研究热处理对Mg-3Sn-1Mn镁合金组织和性能的影响。结果表明,热处理对Mg-3Sn-1Mn镁合金的组织和性能有明显影响。当在420℃固溶处理后,合金中的大多数Mg2Sn相溶入基体。但在250℃时效处理后,在时效合金的晶界和晶内析出大量细小的Mg2Sn相,从而时效合金的抗拉性能和蠕变性能被明显改善,其强化机理可能与α-Mg基体中Mg2Sn相的弥散析出有关。     

两种焊接工艺下14MnVTiRe钢焊接接头的耐蚀性

通过室内挂片和电化学试验,结合微观分析,研究了14MnVTiRe钢两种焊接接头的腐蚀行为,分析影响接头耐海水腐蚀性能的主要因素。结果表明：14MnVTiRe钢两种焊接接头均以母材的耐蚀性较差,热影响区的耐蚀性相对较好;接头各区中微观组织特别是夹杂物类型的不同,是导致接头各区耐蚀性差异的主要影响因素;埋弧焊接头的耐腐蚀性优于手工焊接头,焊接线能量较高可能是主要原因。     

Ca及其含量对快速凝固Mg-Zn合金组织和性能的影响

采用雾化-双辊急冷法成功制备了快速凝固（RS）Mg-Zn-Ca合金薄片,分析了不同含量的Ca对RS Mg-Zn合金微观组织、物相种类和热稳定性的影响。结果表明,RS Mg-6Zn合金的组织细小,晶粒尺寸为6～10μm,其相组成为α-Mg、Mg51Zn20相及少量的MgZn2和Mg2Zn3相。随着Ca的加入及其含量的增加,合金的组织显著细化（达到3～5μm）、析出相的数量大幅度增加,同时低熔点的Mg51Zn20相逐渐被大量热稳定的Ca2Mg6Zn3和Mg2Ca相替代,有效地阻碍了高温下晶界的运动,从而有助于合金组织热稳定性的提高;其中,RS Mg-6Zn-5Ca合金最为显著。     

Comparison of effects of cerium, yttrium and gadolinium additions on as-cast microstructure and mechanical properties of Mg-3Sn-1Mn magnesium alloy

The effects of Ce, Y and Gd additions on the as-cast microstructure and mechanical properties of Mg-3Sn-1Mn alloy were investigated and compared by using optical and electron microscopies, X-ray diffraction analysis, and tensile and creep tests. The results indicated that the microstructure of the Mg-3Sn-1Mn alloy with the addition of 0.87 wt.%Ce was refined while the microstructures of the alloys with the additions of 0.79 wt.%Y or 0.84 wt.%Gd were coarsened. Furthermore, adding 0.87 wt.%Ce to the Mg-3Sn-1...     

Numerical and physical simulation of new SPD method combining extrusion and equal channel angular pressing for AZ31 magnesium alloy

A new serve plastic deformation(SPD) including initial forward extrusion and subsequent shearing process(ES) was proposed.The influence of the ES forming on the grain refinement of the microstructure was researched.The components of ES forming die were manufactured and installed to Gleeble1500D thermo-mechanical simulator.The microstructure observations were carried out on the as-extruded rods(as-received) and ES formed rods.From the simulation results,ES forming can increase the cumulative strain enormousl...     

Comparison of as-cast microstructure,tensile and creep properties for Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys

The as-cast microstructure,tensile and creep properties of Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys were investigated and compared by using optical microscopy and scanning electron microscopy,X-ray diffraction analysis and tensile tests. The results indicate that the as-cast microstructures of Mg-3Sn-1Ca and Mg-3Sn-2Ca alloys are different.The former is mainly composed ofα-Mg,eutectic CaMgSn and solid state precipitation of Mg 2 Sn,whereas the latter is mainly composed ofα-Mg, primary CaMgSn,eutectic CaMgSn and Mg2Ca phases.As a result,the two alloys obtain different tensile and creep properties. Mg-3Sn-1Ca alloy shows relatively higher ultimate tensile strength and elongation at room temperature and 150℃than Mg-3Sn-2Ca alloy,however,the yield strengths of Mg-3Sn-1Ca alloy at room temperature and 150℃are relatively low.In addition,the creep properties of Mg-3Sn-1Ca alloy at 150℃and 70 MPa for 100 h are obviously lower than those of the Mg-3Sn-2Ca alloy.     

10Ni2CrMoV钢焊接接头腐蚀特性研究

通过室内挂片和电化学测试试验,结合微观分析,比较了手工焊和埋弧焊工艺制备的10N i2CrMoV钢焊接接头的腐蚀特征,讨论了相关因素的影响。结果表明:两种工艺的焊接接头均以焊缝金属的耐蚀性最差,热影响区的耐蚀性最好;接头各区中的化学成分和微观组织的差别,是导致接头各区耐蚀性差异的主要因素;埋弧焊接头的耐蚀性优于手工焊接头的,焊接过程中输入的线能量较高是主要原因。     

Zn与Al质量比对Mg-Zn-Al三元镁合金铸态组织和凝固行为的影响

研究了Zn与Al质量比对Mg-Zn-Al三元镁合金铸态组织和凝固行为的影响。结果表明：Zn与Al质量比小于2的实验合金主要由α-Mg＋Mg32（Al, Zn）49相组成，且随着Zn与Al质量比的增加，实验合金中第二相的数量逐渐减少，同时其分布由连续网状逐渐向断续状转变；Zn与Al质量比大于2的实验合金则主要由α-Mg＋Mg32（Al, Zn）49＋MgZn相组成，且随着Zn与Al质量比的增加，实验合金中第二相的数量逐渐增加，同时其分布由断续网状逐渐向颗粒弥散状转变；此外，Zn与Al质量比小于2的实验合金的第二相转变开始温度和峰值温度基本上高于Zn与Al质量比大于2的实验合金，从而导致第二相转变过程中不同相变的发生和第二相类型的不同。     

Effects of various Mg-Sr master alloys on microstructural refinement of ZK60 magnesium alloy

The effects of various Mg-Sr master alloys(conventional as-cast,rapidly-solidified,rolled and solutionized) on microstructural refinement of ZK60 magnesium alloy were investigated.The results indicate that the refinement efficiency of various Mg-Sr master alloys in ZK60 alloy is different.The rolled Mg-Srmaster alloy is found to have relatively higher refinement efficiency than the conventional as-cast,solutionized and rapidly-solidified Mg-Sr master alloys.After being treated with the rolled Mg-Sr maste...