Strengths and ductility of Mo–TiC alloys after secondary recrystallization

A series of Mo–TiC alloys were heated in vacuum at 2473 K for 36 ks. First grain growth behavior was observed using a scanning electron microscope. Then effects of TiC addition on the strengths and ductility at low temperature were discussed from the viewpoints of chemical composition and grain structure.

Materials with TiC additions of not larger than 0.1% demonstrated a single-crystalline grain structure. Both yield and maximum strengths increased by TiC addition and consequently ductility was improved.     

富Ag的Ag—Cu合金再结晶

用度测量、示差扫描量热（ＤＳＣ）、金相显微镜、透射电镜等技术研究了富Ａｇ的Ａｇ－Ｃｕ合金的再结晶。对合金再结晶温室随Ｃｕ含量的变化规律以及在相同变形量下，Ｃｕ含量对合金再结晶过程中冷加工储存能的释放的影响进行探索，并讨论了结果。     

介绍一种生产冲挤用铝合金坯料的新工艺

哈兹列特铝板带连铸连轧工艺已被成功地用于铝和铝合金冲击挤压用坯料的生产。在对哈氏四个有关用户扫描的基础上，列举了其产品及其用途，并介绍了相关工艺及其优点。     

Al-4%Cu过饱和合金在强磁场中时效行为

采用差示扫描量热仪分析并结合显微硬度测试、电子探针分析、透射电镜观察研究了10-T稳恒强磁场对Al-4％Cu（质量分数）合金130℃时效过程中各沉淀相析出行为的影响。结果表明：在低温时效初期强磁场的引入加速了铜的扩散，降低了G.P.（Ⅰ）区的溶解激活能，促进其溶解，各沉淀相的析出与溶解温度均向低温处移动，时效进程加快；另外，强磁场时效后沉淀相尺寸减小；施加强磁场试样的硬度明显高于未施加磁场试样的，时效硬化效果加强。     

The magnetic applications choice among ferrite ceramics,metallic strips,or metal powder cores

Iron-based metallic strip materials such as iron, silicon-iron, and amorphous metal are used for low frequency (50–60 Hz. line) power applications. Low-loss Nickel-based alloys as high permeability strip or insulated powder cores are the choices for stable, low-level higher frequency applications. Iron-based powder cores offer low cost as power supply filter chokes. Ceramic ferrites combine highest frequency operation with low cost and reduced component size as transformers and chokes in telecommunication and high frequency power supply applications.     

A universal dependence for thermal conductivity of metals and dilute alloys

A universal curve relating the maximum of thermal conductivity and its respective temperature with the residual electrical resistivity has been proposed for metals and dilute alloys. Based on the equation of that curve, a comparative analysis of selected literature data of thermal conductivity of metals, which have residual electrical resistivity in the range 10^–11<₀<10^–5. cm, have been performed. Using the data for 33 metals, confirmation of the Wiedemann-Franz law for the impurity component/T of thermal conductivity was obtained, which means that _th/_el1, where _th and _el are the parameters of the electron-lattice defect interaction obtained from measurements of thermal and electrical conductivity, respectively. Examples of the failure of the Wiedemann-Franz law are also presented, exhibiting the values of _th/_el in the range 0.16 to 25. Measurements of thermal conductivity in the range 2 to 20 K and determination of the residual electrical resistivity for the samples of Cd doped with Zn and quenched were performed, resulting in values _th/_el1.     

Magnetic and mössbauer studies on ductile Fe-Cr-Co permanent magnet alloys

Iron-chromium-cobalt alloys possess attractive magnetic properties combined with good formability and hence are identified as technologically important magnetic materials. Alloys with compositions Fe-28·9 Cr-15·6 Co and Fe-28·4 Cr-20·1Co (weight percent) have been studied. Heat-treatment parameters during thermomagnetic treatment viz temperature, time and external magnetic field were optimized with reference to magnetic properties. The fully treated anisotropic alloys develop remanence=11·5–12·0 kilo Gauss, coercivity=600–650 Oersted and energy product=4–4·5 million Gauss Oersted. Electron microscopic and Mössbauer spectroscopic techniques were used to identify the original and transformed phases. During the various stages of the development of the alloy, the changes in mechanical hardness were correlated with magnetic hardness.     

Influence of silicon on the oxidation of titanium between 550 and 700°C

The oxidation behavior of Ti-Si alloys (0.25, 0.5, and 1 Wt. % Si) was investigated between 550 and 700°C; in oxygen by continuous thermogravimetry for a maximum duration of about 500 hr and, in air by daily weighing for durations from a few hundred to several thousand hours. The kinetics results revealed that the presence of silicon leads to a decrease in oxidation rate which is more evident when the temperature is raised and the silicon content is increased. Morphological and structural examinations revealed that silicon modifies the internal architecture of oxide layers when compared with unalloyed titanium; in particular, reduced porosity in the layers is observed. Analysis showed that silicon is uniformly distributed in the oxide layer. However, while part of the silicon is in solid solution in the rutile, some is also precipitated as small crystals ( <1 m at 850°C) of SiO₂, of cristobalite structure. The adherence of oxide layers to the metal substrate was measured after cooling of samples; the addition of silicon has been observed to modify, in a manner dependent on its content, the adherence of oxide layers.     

Study on structure and magnetic entropy changes of Ce2-xPrxFe16.5Co0.5 alloys

A series of Ce2-xPrxFe16.5Co0.5 alloys were preparedby arc melting under purified argon atmosphere. The structure and magnetic entropy changes in Ce2-xPrxFe16.5Co0.5 alloys were investigated by means of X-ray diffraction pattern and MPMS XL-7 magnetometer. The experimental results show that the crystal structure of Ce2-xPrxFe16.5Co0.5 alloys keeps in TH2Zn17-type rhombohedral, and the Curie temperature of Ce2-xPrxFe16.5Co0.5 alloys can be shifted to room temperature around by a composition adjustment. The magnetic entropy changes (-ΔSM) in Ce2-xPrxFe16.5Co0.5 alloys are relatively large, and a platform of magnetic entropy changes appearsnear the temperature TC. Ce2-xPrxFe16.5Co0.5 alloys are the potential working media for magnetic refrigeration with their stable chemical properties and especially low price.     

稀土元素对钯室温电学性能的影响

研究了稀浓度(0.6at％以下)稀土元素(La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Er、Yb)对钯的室温电学性能的影响。所有稀土元素均提高钯的电阻率(p)、降低电阻温度系数(α),实验结果与理论分析证明(p·α)_((?)d-RE)d=(p·α)_(Pd)。Gd以前的稀土元素降低钯的对铜热电势(ε),其余重稀土元素增大钯的对铜热电势。按0.1at％RE归一化处理的实验数据表明,轻稀土元素对钯电阻率的影响稍大于重稀土,但Ce、Eu、Yb呈反常影响,化合价和尺寸因素是影响电学性能的主要因素。