EFFECT OF PROGRESSIVE AGING TREATMENT ON THE PROPERTIES AND MICROSTRUCTUR

ＥＦＦＥＣＴＯＦＰＲＯＧＲＥＳＳＩＶＥＡＧＩＮＧＴＲＥＡＴＭＥＮＴＯＮＯＮＴＨＥＰＲＯＰＥＲＴＩＥＳＡＮＤＭＩＣＲＯＳＴＲＵＣＴＵＲＥＯＦＴＨＥＨＩＧＨ－ＨＡＲＤＥＬＡＳＴＩＣＮＩＣＫＥＬ－ＣＨＲＯＭＩＵＭ－ＡＬＵＭＩＮＩＵＭＡＬＬＯＹ￥ＬＩＵＧｕｉ...     

ELECTROCHEMICAL PROPERTIES OF THE HYDROGEN ABSORPTION OF AMORPHOUS Ml－Ni ALLOY FILMS

ＥＬＥＣＴＲＯＣＨＥＭＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＴＨＥＨＹＤＲＯＧＥＮＡＢＳＯＲＰＴＩＯＮＯＦＡＭＯＲＰＨＯＵＳＭｌ－ＮｉＡＬＬＯＹＦＩＬＭＳ￥ＨＵＷｅｉｋａｎｇ;ＺＨＡＮＧＹｕｎｓｈｉ;ＳＯＮＧＤｅｙｉｎｇ;ＬＵＯＤａｏｊｕｎ;ＷＡＮＧＹｕｎ...     

THE ESTABLISHMENT OF CALCULATION FORMULA FOR CASTING－ROLLING FORCE OF VISCOUS FLUID AND THE INFLUENCE OF TECHNOLOGICAL FACTORS

ＴＨＥＥＳＴＡＢＬＩＳＨＭＥＮＴＯＦＣＡＬＣＵＬＡＴＩＯＮＦＯＲＭＵＬＡＦＯＲＣＡＳＴＩＮＧ－ＲＯＬＬＩＮＧＦＯＲＣＥＯＦＶＩＳＣＯＵＳＦＬＵＩＤＡＮＤＴＨＥＩＮＦＬＵＥＮＣＥＯＦＴＥＣＨＮＯＬＯＧＩＣＡＬＦＡＣＴＯＲＳ￥Ｓｕｎ，Ｂｉｎｙｕ；Ｚｈａｎ...     

NEW METHOD OF EXTRACTING GOLD AND SILVER FROM HIGH SILVER-GOLD CONCENTRATES

ＮＥＷＭＥＴＨＯＤＯＦＥＸＴＲＡＣＴＩＮＧＧＯＬＤＡＮＤＳＩＬＶＥＲＦＲＯＭＨＩＧＨＳＩＬＶＥＲ－ＧＯＬＤＣＯＮＣＥＮＴＲＡＴＥＳ￥Ｓｏｎｇ，Ｑｉｎｇｓｈｕａｎｇ；Ｗａｎｇ，Ｄｅｑｕａｎ（ＤｅｐａｒｒｍｅｎｔｏｆＮｏｎｆｅｒｒｏｕｓＭｅｔａｌｌｕｒｇ...     

THEORETICAL ANALYSIS AND DESIGN／CALCULATION FORMULAE FOR HYDRAULIC IMPACT MECHANISM

ＴＨＥＯＲＥＴＩＣＡＬＡＮＡＬＹＳＩＳＡＮＤＤＥＳＩＧＮ／ＣＡＬＣＵＬＡＴＩＯＮ　ＦＯＲＭＵＬＡＥＦＯＲ　ＨＹＤＲＡＵＬＩＣＩＭＰＡＣＴＭＥＣＨＡＮＩＳＭＨｅ；Ｑｉｎｇｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｃｅｎ...     

ANALYSES OF ENERGY LOSSES AND ACCUMULATOR AND PARAMETERS DESIGN METHOD OF HYDRAULIC IMPACTOR MECHANISM

ＡＮＡＬＹＳＥＳＯＦＥＮＥＲＧＹＬＯＳＳＥＳＡＮＤＡＣＣＵＭＵＬＡＴＯＲＡＮＤＰＡＲＡＭＥＴＥＲＳＤＥＳＩＧＮＭＥＴＨＯＤＯＦＨＹＤＲＡＵＬＩＣＩＭＰＡＣＴＯＲＭＥＣＨＡＮＩＳＭ￥Ｈｅ，Ｑｉｎｇｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎ...     

EFFECTS OF THERMAL CYCLE ON MECHANICAL PROPERTIES OF SiC PARTICLES REINFORCED MoSi_2 COMPOSITE

ＥＦＦＥＣＴＳＯＦＴＨＥＲＭＡＬＣＹＣＬＥＯＮＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＳｉＣＰＡＲＴＩＣＬＥＳＲＥＩＮＦＯＲＣＥＤＭｏＳｉ_２ＣＯＭＰＯＳＩＴＥ￥ＺＨＥＮＧＬｉｎｇｙｉ;ＪＩＮＹａｎｐｉｎｇ;ＬＩＰｅｎｇｘｉｎｇ（ＴｈｅＳｔａｔｅ?..     

STRAIN INDUCED STRUCTURAL TRANSITION OF INTERFACES AND TWINS IN A HOT－DEFORMED DUAL－PHASE TIAL ALLOY

ＳＴＲＡＩＮＩＮＤＵＣＥＤＳＴＲＵＣＴＵＲＡＬＴＲＡＮＳＩＴＩＯＮＯＦＩＮＴＥＲＦＡＣＥＳＡＮＤＴＷＩＮＳＩＮＡＨＯＴ－ＤＥＦＯＲＭＥＤＤＵＡＬ－ＰＨＡＳＥＴＩＡＬＡＬＬＯＹＣＨＥＮＧｕｏＦｉａｎｇ；ＷＡＮＧＪｉｎｇｕｏ；ＺＨＡＮＧＬｉｃｈｕｎａｎｄ...     

FRACTURE MECHANICS ANALYSIS OF THERMAL STRAINFATIGUE LIFE FOR THE SINTERING MACHINE PALLET

ＦＲＡＣＴＵＲＥＭＥＣＨＡＮＩＣＳＡＮＡＬＹＳＩＳＯＦＴＨＥＲＭＡＬＳＴＲＡＩＮＦＡＴＩＧＵＥＬＩＦＥＦＯＲＴＨＥＳＩＮＴＥＲＩＮＧＭＡＣＨＩＮＥＰＡＬＬＥＴＬＩＺｈｅｎｚｉａｎｄＬＩＭｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＡｒｃｈｉｔｅｃｔｎｒｅＥｎｇｉ...     

MECHANICAL ANALYSIS AND NUMERICAL CALCULATION OF BONDING STRENGTH MEASUREMENT BY INTERFACIAL INDENTATION METHOD

ＭＥＣＨＡＮＩＣＡＬＡＮＡＬＹＳＩＳＡＮＤＮＵＭＥＲＩＣＡＬＣＡＬＣＵＬＡＴＩＯＮＯＦＢＯＮＤＩＮＧＳＴＲＥＮＧＴＨＭＥＡＳＵＲＥＭＥＮＴＢＹＩＮＴＥＲＦＡＣＩＡＬＩＮＤＥＮＴＡＴＩＯＮＭＥＴＨＯＤ①ＹｉＭａｏｚｈｏｎｇ１,ＨｕａｎｇＢａｉｙｕｎ１,...     

Relationship between half-cell potential and corrosion level of rebar in concrete

This work studies the influence of various parameters, such as temperature and humidity, fly ash content and chloride concentration, on the relationship between half-cell potential and the corrosion level of rebar in concrete. Results show that the half-cell potential decreases with an increase in temperature under the same corrosion level of rebar, and half-cell potential decreases with an increase in corrosion level of rebar under the same temperature. The half-cell potential decreases with an increase in chloride concentration and increases with an increase in fly ash content when fly ash content is lower than 50% under the same corrosion level of rebar, and the half-cell potential decreases with an increase in the corrosion level of rebar under the same chloride concentration and fly ash content.     

Thermophysical properties of lanthanum zirconate coating prepared by plasma spraying and the influence of post-annealing

Nano-scaled lanthanum zirconate powder prepared by co-precipitation–calcination method was plasma-sprayed into a thick coating on an alloy substrate. We investigated the thermophysical properties of the free-standing coating, including thermal conductivity and thermal expansion coefficients (TECs). Minimum value of the thermal conductivity (at 900 °C) of the coating was about 0.73 W m⁻¹ K⁻¹, and the average TEC in the measurement range was about 9.45 × 10⁻⁶ K⁻¹. Although the TEC value was similar to that of the bulk material, the change tendency versus temperature was different. After annealing at 1300 or 1400 °C for 50 h, we found that the heat insulation performance of the coating decreased with the heat treatment temperature, while the hardness and fracture toughness increased. A peak of sudden decrease in TEC value can be observed in the curve, and with increasing temperature, the peak shifted to high-temperature direction.     

Thermal-expansion anisotropy of orthorhombic martensite in the two-phase (α + β) titanium alloy

Anisotropy of the thermal expansion coefficient (TEC) has been revealed along the axes of the crystal lattice of the α″ titanium martensite in the two-phase (α + β) titanium alloy of grade VT16 (Ti–3Al–5V–4.5Mo, wt %). It has been established by the method of in situ X-ray diffraction analysis that the lattice parameter b of the orthorhombic martensite obtained by quenching from different temperatures decreases upon heating. The TECs along the axes of the crystal lattice of the martensite obtained by quenching from different temperatures have been calculated. It has been shown that the uniaxial extension of bars of the VT16 alloy quenched for the metastable β phase with relative deformations of 0.7, 1, 2, 3, 4, 5, 6, and 8% leads to the formation of the deformation-induced martensite with an axial texture along the b direction of the martensite lattice. In the course of dilatometric studies of the deformed bars, it has been established that there are two temperature intervals (from–100 to +70°C and from 150 to 300°C) with a low TEC. In the first interval, the value of the TEC varies from–2 × 10^–6 to +8 × 10^–6 K^–1 and is determined by the volume fraction of the oriented α″ martensite. This Invar effect is one-dimensional and is manifested along the b axis of the martensite.     

Experimental investigation of time dependent non-linear 3D relationship between critical carbonation depth and corrosion of steel in carbonated concrete

Abstract

This paper aims at the experimental investigation of time dependent non-linear relationship between critical carbonation depth and corrosion rate of steel in carbonated concrete by laboratory controlled experimentation under severe environmental condition. In this research, three-dimensional experimental observations are taken consecutively involving carbonation depth, half-cell potential and elapsed time as well as the gravimetric corrosion mass loss. The experimental observations revealed an interesting non-linear relationship between the above said measurements due to the varying resistivity of carbonated concrete. It is also found that the carbonation induced corrosion does not start until the carbonation depth reaches a certain critical level from the steel rebar and the half-cell potential values become constant after carbonation reaches the critical depth and then start rising again after carbonation reaches the rebar level.     

PREPARATION OF HIGH THERMAL EXPANSION COEFFICIENT PORCELAINS FUSED TO METALS

Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on metals, high TEC porcelains are needed. In this research, the high TEC phase leucite (KAlSi2 O6) in the high TEC porcelain was prepared by sol-gel method. The crystal size of leucite made by sol-gel is about 77nm through controlling the process parameters. The process from xerogel to leucite was investigated by means of DSC (differential scanning calorimetry), TG (thermogravimetry), XRD ( X-ray diffraction) and IR (infrared absorption spectrum). Leucite had been detected after the gel was treated at 900℃, this formation temperature is about 250℃ lower than that of melting method. The porcelain made from 50% of the leucite powder and 50% of low fused temperature frit has an average TEC of 19.2×10-6/℃ C from room temperature to 450℃, which is much higher than the common porcelains.     

Improved concrete bridge deck evaluation using GPR by accounting for signal depth–amplitude effects

Ground-penetrating radar (GPR) surveys have tended to provide unpredictable accuracy in estimating areas of corrosion-induced damage in reinforced concrete bridge decks. Six in-service reinforced concrete bridge decks with exposed (unpaved) concrete wearing surfaces were surveyed using GPR to evaluate internal corrosion-induced damage for comparison against the chain drag and half-cell potential survey methods. A normalization procedure for removing GPR signal losses resulting from depth-dependent two-way travel time variations in the data was developed and thresholds for predicting chain-drag and half-cell potential-based estimates of deterioration quantity and location were established. Thresholds established using the amplitude–time correction provided significant improvements in the spatial and quantitative predictive capabilities of GPR for delineating corrosion-induced damage.     

掺钙的铬酸镧粉末制备工艺及烧结性能研究

采用固相法在不同工艺条件下烧结合成了掺钙的铬酸镧(La1-xCaxCrO3)粉末。对粉末进行了X射线衍射分析，用扫描电镜对烧结后试样的微观形貌进行观察，分析了钙含量及合成条件对试样晶体结构及烧结性能的影响。研究发现，微量钙的加入对晶体结构影响较小，但明显促进烧结致密化；随着粉体合成温度升高，烧结试样断面收缩率略有增大。合成温度决定粉体相结构，合成反应在1h内基本完成，延长合成时间对品体结构的影响不大。     

燃烧合成TiAl3化学反应动力学研究

用Friedman法研究了非等温DSC条件下燃烧合成反应Ti 3Al→TiAl3的复杂反应动力学，该合成反应并非单步合成反应，而是有中间相TiAl出现的多步反应，它包含三个子过程，其激活能分别为109，175和89KJ/mol，控制反应速度的这三个过程分别对应反应初期的Ti(固）和Al(液）间的直接反应，吕期的Ti-Al扩散偶中Al通过TiAl3层的扩散以及反应后期的TiAl-Al扩散偶中Al通过TiAl3层的扩散。     

改进型Fe_3O_4磁流体的研制及带膜磁畴观察

利用化学反应的方法研制了一种带膜观察磁畴结构的改进型磁流体—Ｆｅ３Ｏ４磁流体,并对其生成条件及影响其磁性的因素进行了分析．实验表明：当ＦｅＣｌ２·４Ｈ２Ｏ：ＦｅＣｌ３·６Ｈ２Ｏ：ＮａＯＨ＝１：１：６（摩尔比）时最容易生成稳定的Ｆｅ３Ｏ４．在反应过程中,水质的好坏及有无搅拌是影响 Ｆｅ３Ｏ４磁流体颗粒大小及磁性的主要因素．对Ｚ８牌号的硅钢片进行带膜磁畴观察表明,该磁流体能够实现带膜观察,成纹性及重现性较好,而且磁稳定性也较好,未经任何处理的Ｆｅ３Ｏ４磁流体可以放置一周左右而磁性不发生变化;用去离子水清洗至ｐＨ值为７并且隔绝空气后,可放置更长时间．     

粉末冶金法制备镁基复合材料的力学性能和增强机理研究

为了探讨MWNTs对镁基复合材料力学性能的影响和增强机理,采用粉末冶金的方法制备了多壁碳纳米管增强镁基复合材料,对其力学性能进行了测试,并对显微组织进行了观察和分析.结果表明:碳纳米管在基体中呈束状分布,没有出现团聚现象;MWNTs与镁基之间并没有反应发生,碳纤维与镁基体并未在界面处形成碳镁化合物;它们之间是无任何化学作用的机械结合;复合材料的硬度随着MWNTs含量的增加而增加,强度也相应提高;镁基复合材料的强化主要来自增强体的强化作用、细晶强化和析出强化.