国内钛合金近几年学术研究进展

在钛合金研发受到高度重视的同时,相关钛合金的基础研究国内也较重视,取得了较好的成绩,如发展的近β锻造技术、准β锻造技术、三态组织、阻燃机理、低温变形机理、原子与空位的交互作用等等。本文综述了国内钛合金近几年的学术研究进展。     

Ti-45Al-10Nb合金的高温氧化行为

研究了Ti—45A1—10Nb(原子分数，％)合金在800-960℃在氧气和空气中的氧化行为．结果表明，该合金具有较好的高温抗氧化性能，其氧化增重速率与铁基耐热不锈钢相似或略优．与Ti—50A1合金相反，Ti-45A1-10Nb合金在空气中的氧化增重速率明显低于在纯氧中的氧化增重速率．X射线衍射与能谱分析表明，Ti-45Al一10Nb合金在氧气中的氧化产物主要有TiO2和Al2O3，但在空气中的氧化产物中有TiN相．这是降低氧化速率的主要原因，同时，合金元素Nb稳定了氧化层中的TiN相，因而提高了合金在空气中的抗氧化性能．     

Monte Carlo simulation of hydrogen absorption in palladium and palladium–silver alloys

A modified Monte Carlo (MC) simulation was performed to investigate the hydrogen absorption behavior in Pd and Pd–Ag alloys of the composition Pd_xAg_1−x (x=0.7–0.8) under H₂ pressure (0.1 MPa) at different temperatures. The present method employed can consider the dissociative adsorption of hydrogen molecule and the subsequent absorption of hydrogen atom by formalizing the relationship between the pressure of hydrogen molecule and hydrogen atom. The potential parameters were determined to reproduce the solution enthalpy of hydrogen in pure metals. The results are in good agreement with experimental findings as well as previous theoretical studies. We confirmed that our method is useful to simulate the absorption of hydrogen in metals and alloys.     

振动筛合金篦条磨损机理及抗磨损技术

分析了山西焦化股份有限公司振动筛合金篦条磨损情况，对合金篦条磨损机理进行了研究，提出控制磨蚀和提高材料耐磨洼的方法。     

Properties of Quaternary Alloy Magnetic Semiconductor (InGaMn)As Grown on InP

We have studied properties of quaternary alloy magnetic semiconductor (InGaMn)As grown on InP substrates by low-temperature molecular-beam epitaxy (LT-MBE). A large MCD peak whose intensity is larger than 500 mdeg for (InGaMn)As was observed. This peak intensity was about three times larger than that of typical (GaMn)As films. Relatively high Curie temperature of 83 K of [(In_0.53Ga_0.47)_0.88Mn_0.12]As was observed by Hall measurements. The carrier concentration of [(In_0.53Ga_0.47)_0.88Mn_0.12]As was estimated to be more than 1.0 × 10²¹ cm^–3 by using the Curie–Weiss fitting of the Hall coefficient R _H, indicating that more than 40% of Mn atoms are activated. This means that (InGaMn)As has a higher activation ratio of Mn as acceptors than (GaMn)As.     

纯镁对碳化硼颗粒的常压浸渗

本文研究了纯镁对不同致密度的碳化硼(B₄C)颗粒基片的常压浸渗性;讨论了镁液对B₄C颗粒聚集体常压浸渗的影响因素;提出了浸渗模型。研究表明,纯镁在氩气保护下,800～850℃温度范围保温30min即可浸渗B₄C颗粒聚集体。浸渗深度和宽度随加热温度升高和保温时间延长而增加;常压浸渗的B₄C_P/Mg复合材料具有很高的硬度,B₄C颗粒在基体中分布较均匀。     

Effect of heat treatments on tensile properties and microstructures of wrought Mg−Zn−Zr-RE alloys

The effect of heat treatments on the tensile properties and microstructures of wrought Mg–Zn–Zr-Rare earth alloys MB25 and MB26 have been studied in this paper. It was shown that the homogenization of the cast ingots decreased the strength of the extruded bars because some grain boundary phases were dissolved during the process of this treatment, while the ageing treatment of the extruded bars increased the strength due to the dispersive precipitation of MgZn₂ phase. The quenching + ageing treatments of the extruded bars decreases the strength and plasticity because of the growing up of the grains.Abbreviations ED electron diffraction - GB grain boundary - RE rare earth - TEM transmission electron microscope     

含钡合金在钢液中的脱氧行为研究

在MoSi2炉上采用MgO质坩蜗对钢管进行了含钡合金脱氧行为的研究。实验中钡系合金主要选取SiAUBa、SiCaBa、SiAlBaCa、SiAlBeCaSr及用于钙处理的SiCa包芯线，选用Al作为对比脱氧剂，考察了钡系合金脱氧的全氧含量，脱氧产物的分布、尺寸和形貌，探讨了钡系合金脱氧和对夹杂物变性作用的机理。     

高能超声处理对锡锑包晶合金凝固组织的影响

在锡锑包晶合金的凝固过程中导入高能超声，不仅显著细化α相和β相晶粒组织，同时使具有立方晶体特征的β相组织有明显的球化趋势，消除了密度偏析，分析了高能超声细化凝固组织的机理。     

RNA结合蛋白RB47、RB60在叶绿体翻译调节中的作用

光调节的叶绿体mRNA的翻译需要mRNA5′,非翻译区(5′ UTR)相互作用的中间作用因子.叶绿体多聚腺苷酸结合蛋白(cPABP)RB47特异性地与PsbAmRNA的5′ UTR结合,并对于该mRNA的翻译是很重要的.定位于叶绿体中与cPABP伴随纯化出来的一种蛋白质二硫化物异钩酶RB60表现出调节cPABP与PsbAmRNA的5′ UTR结合的特性.这种调节是通过可逆地改变有氧化还原特征的cPABP的氧化还原状态来实现,或通过ADP依赖的磷酸化来实现.这种机制就在调节叶绿体的基因表达中提供了一个简单可逆的开关机制.