IrO2-pH微电极的研制及钢筋/混凝土界面pH的测量

采用电化学阳极氧化和高温碳酸盐氧化两种方法制备 IrO2-pH微电极，其特点是对氢离子响应快、线性范围宽、机械性能好、具有长期稳定性 .考察了该电极的pH响应特性、化学成分、机械性能等.结果表明，这种IrO2-pH微电极 适用于钢筋/混凝土界面pH值的原位测量.     

CREEP CRACK PROPAGATION IN CONVENTIONAL CAST AND DIRECTIONALLY SOLIDIFIED SUPERALLOY RENE 80

The creep crack propagation in superalloy René80 of two different microstructures,i.e.,equiaxed grain structure by conventional casting and columnar grain by directionalsolidification,was investigated under static load at 1123 K.The creep crack growth rate,da/dt,seems to be correlated with the stress intensity factor,K.The creep crack growth ratein the directionally solidified alloy is lower than that in the conventional cast alloy,owing tothe elimination of transverse grain boundaries.The effect of microstructure on creep crackpropagation has also been discussed.     

34CrMoA转子钢高温循环蠕变断口分形维数与蠕变性能的关系

用垂直剖面法测定了34CrMoA转子钢在550℃循环蠕变断口的分形维数,分析、比较了分形维数与蠕变性能的关系,结果表明,分形维数与断裂应变呈线性关系。     

晶界碳化物对Fe-Cr15-Ni25合金蠕变裂纹扩展行为的影响SCIEI

在两种不同晶界状态下研究了Fe-Cr15-Ni25合金的蠕变裂纹扩展行为。单相合金的空洞在晶界三叉点处形核,而对晶界上有碳化物析出的合金,空洞在晶界碳化物上形核。晶界碳化物阻碍了空洞的长大和连接,因而大大提高了蠕变裂纹扩展抗力。     

小冲孔蠕变试验技术

小冲孔蠕变试验技术是获取在役构件蠕变性能的一种新方法，由于它具有接近无损取样的特点，因此受到学术界和工业界的广泛重视。本文简要回顾了小冲孔蠕变试验技术的发展及应用，重点介绍了典型小冲孔蠕变试验装置的组成及结构，指出了小冲孔蠕变试验技术目前存在的问题和广阔的应用前景。     

Ti-25V-15Cr-2Al-2Mo-0.2C阻燃β钛合金的蠕变变形结构研究

采用TEM技术研究了具有不同热处理组织的Ti-25V-15Cr-2A1-2Mo-0．2C合金存在540℃，250MPa，100h蠕变作用后的变形结构。结果表明：位错环组是合金蠕变变形结构中的典型位错组态；合金的蠕变抗力随β基本上弥散分布的第二相析出数量的增加而提高。添加微量能提高蠕变抗力的合金元素，如Si元素等，是改善合金蠕变性能的可行途径。     

High-temperature corrosion and creep of Ni-Cr-Fe alloys in carburizing and oxidizing environments

The carburization of NiCr 32 20 and NiCrSi 60 16 has been studied in CH₄-H₂ mixtures in the temperature range 900–1100°C. The methods included thermogravimetric measurements and studies on reacted specimens by X-ray diffraction, metallographic, and chemical analysis. Upon carburization internal carbides M₇C₃ and M₂₃C₆ are formed (M=mainly Cr); the rate of carburization is determined by carbon diffusion in the Fe-Ni matrix with carbide precipitations. The effect of the alloying elements Ni and Si on the carburization resistance of austenitic alloys is explained. By the same methods the oxidation and carburization in CO-H₂O-H₂ mixtures have been studied. The important role of a stable chromium oxide layer for the carburization resistance was confirmed. Creep tests at 1000°C in a CO-H₂O-H₂ atmosphere where Cr₂O₃ is stable showed carburization occurring through cracks in the oxide layer. At high strain rates premature failure occurs by carburization, which is followed by internal oxidation and formation of cracks, voids, and holes.     

混凝土小砌块与普通砖混住宅楼造价分析

指出混凝土小型空心砌块是一种节能型的新型墙体材料。本文从经济角度对该种材料和粘土砖材料进行了实例分析、比较,得出了这种新型材料值得推广使用的结论。     

Creep-induced local lattice parameter changes in a monocrystalline nickel-base superalloy

The γ-γ lattice mismatch of specimens of the monocrystalline nickel-base superalloy SRR 99 has been measured by a high-resolution X-ray diffraction technique for the undeformed state and after high-tem-perature creep deformation. During creep deformation beyond the minimum creep rate (total strain =0.5%), the lattice mismatches, measured in and perpendicular to the [001] stress axis, respectively, un-dergo changes in opposite directions. This reflects the buildup of a complex deformation-induced triaxial state of internal stress in the phases y and γ. The overall resolved shear stresses that act in γ and y due to the combined action of the external and internal stresses are estimated, and the conditions under which cutting of the γ phase by dislocations should occur are discussed.