X射线照相法测量超细金属丝直径

本文基于X射线照相技术与数字图像处理方法,实现了对超细金属丝直径的测量。与扫描电镜测量结果对比分析表明,该方法对超细金属丝直径的测量具有较高的置信度,测量不确定度分析表明,其合成测量不确定度在0.27μm左右。     

退火温度对超细钼丝性能的影响

通过调整退火温度测试不同温度下超细钼丝的力学性能,探讨退火温度对超细钼丝力学性能影响的规律,从而制定钼丝最佳退火工艺.结果表明,在900～1 100℃退火,超细钼丝的延伸率变化不明显,而在1 100～1 350℃退火,延伸率发生了突变;结合断口分析得知,900～1 100℃退火主要发生回复,未消除加工形成的轴向织构,而1 350℃退火,超细钼丝发生了再结晶,完全消除了加工织构,所以综合性能得到改善.依此推荐超细钼丝最佳连续退火工艺参数为:在氢气保护下,移动速度为10 m/min,加热温度在1 350℃左右.     

超细电子级玻璃纤维表面形貌表征与分析

采用光学显微镜(OM)、扫描电子显微镜(SEM)及原子力显微镜(AFM),观察了D450超细电子级玻璃纤维裸丝及原丝表面形貌,分析了表面形貌特征及其形成的原因。结果表明,超细电子级玻璃纤维裸丝在OM图像中呈光滑的圆柱状,细部特征难于呈现,在较低倍率的SEM图像中呈近似圆柱状,在高倍率SEM及AFM图像中呈桔皮状;3种图像中均未见超细电子级玻璃纤维表面有裂纹存在。超细电子级玻璃纤维表面浸润剂膜在OM图像中难于呈现,在SEM图像中主要呈光洁的连续薄膜状,同时伴有颗粒状的凸起、壳片状的凸起等形状。     

超细钨丝

本文研究了用连续电解抛光的方法制造超细钨丝的工艺。建立的一套装置,可以制备直径小于5μ的钨丝。观察了丝材在连续抛光时的行为,讨论了各项工艺参数的影响。使用证明,制得的丝材性能良好。这种工艺不仅可用于超细钨丝的工业生产,也可用于其它金属细丝、薄带的清洗及制备。     

尼龙6,6超细纤维的新进展

ICI 纤维公司在1987年第一次生产出尼龙6,6超细纤维,商品名为 Tactel。它是采用两步法纺丝、全拉伸工艺生产的、102分特/90根的超细纤维,可用来制造滑雪衣、衬衫、运动衣、雨衣、便服等。该公司在1989年着手开发高速纺一步法生产尼龙6,6超细部分取向丝(POY)。公司生产的全拉伸或变形的6,6超细纤维都小于1分特,POY 丝则是在直丝拉伸或变形后成为超细丝。尼龙6,6具有可深着色的优点,这使超细丝能达到可接受的色范围(包括黑色)和水洗牢度的标准。就蓬松性而言,尼龙6,6超细纤维优于尼龙6和聚酯的超细纤维,但比普通尼     

中国超细晶硬质合金及原料制备技术进展

超细晶硬质合金是WC晶粒度≤0.5μm的硬质合金,这类合金具有高强度和高硬度的优异性能。目前由超细晶硬质合金制备的高效刀具已经广泛用于航空航天、核能、汽车、发电设备、新能源和电子通讯等现代制造业。主要对中国超细晶硬质合金原料(例如超细碳化钨粉、钴粉、复合粉)和超细晶硬质合金制备技术、性能及表征方法作了系统的阐述。最后对超细晶硬质合金制备技术进行了展望。     

熔融静电纺制备聚丙烯超细纤维的研究

采用熔融静电纺丝技术制备聚丙烯(PP)超细纤维,运用高速摄影技术记录了PP熔融纺丝液在高压静电场力作用下拉伸成丝的整个过程,并借助扫描电子显微镜( SEM)对不同静电压条件下所制备的PP超细纤维进行表征.实验表明,熔融静电纺射流运里大致可以分为稳定直线、分裂鞭动和沉积3个阶段.随静电压的增加,纺丝射流速度以及射流稳定直线运动区域增加,所制备纤维直径明显降低.     

我国超细粉碎机械现状及发展

超细粉碎机和超细分级机的发展及使用与非金属矿物工业的发展是密不可分的，尤其是近年来，我国非金属矿物工业的发展使得超细粉碎及超细分级技术也得到了进一步提高。本文以此为背景，分析了我国超细粉碎机及超细分级机的现状、超细粉碎机械制造企业存在的问题，及其企业发展的市场空间。     

超细粉碎技术现状及发展趋势

综述了国内外超细粉碎技术及设备的现状、进展,指出了其发展趋势,从工作原理、结构特点等方面详细介绍了超细粉碎典型设备,同时又指出了近年来国内外在此领域中的新进展,基于现存问题指出了今后超细粉碎研究的方向。     

大力发展电池及钨钴合金新材料用钴产品建设有特色的先进的钴镍制造业

从钴镍锰三元材料、超细钴粉良好的市场前景、政府政策的支持及技术基础等方面,阐述了大力发展电池及钨钴合金新材料用钴产品——钴镍锰三元前驱体和超细钴粉的必要性,并对相关制备技术研发的方向与重点提出了建议。     

电爆技术用于超细粉制备和表面喷涂的研究进展

论述了电爆技术用于超细粉制备和材料表面喷涂方面的机理、特点及近年来的研究状况.电爆法制粉能量转化率高、工艺参数调整方便、适应材料广,可用于制备金属合金粉,氧化物和氮化物超细粉,所制粉末具有纯度高、化学活性高、不易团聚等优点.电爆喷涂技术有线电爆、粉末柱电爆、定向粉末电爆、金属箔电爆等类型,能得到晶粒细小高致密的涂层,特别适于喷涂高熔点的材料;分析了电爆制粉和电爆喷涂进一步研究的问题.     

Microstructural Evolution and Thermal Stability of Ultra-fine Grained Al-4Mg Alloy by Equal Channel Angular Pressing

Experiments were conducted to evaluate the grain refinement and thermal stability of ultra-fine grained Al-4Mgalloy introduced by equal-channel angular pressing (ECAP) at 473 K. The results show that the intensities of X-ray(111/222) and (200/400) peaks for the alloy processed by ECAP decrease significantly and the peak widths of halfheight become broadening compared with the corresponding value in the annealed alloy. The microstructure of 2passes ECAPed alloy consists of both elongated and equiaxed subgrains. The residual strain in the alloy increaseswith increasing passes numbers, that appears as increasing dislocation density and lattice constant of matrix. Anequiaxed ultra-fine grained structure of～0.2μm is obtained in the present alloy after 8 passes. The ultra-fine grainsare stable below 523 K, because the alloy retains extremely fine grain size of～1μm after static annealing at 523 Kfor 1 h.     

高强度合金无氧铜导电线材研究

本文介绍了高强度合金无氧铜导电线材的成分设计和强化机理，对合金线材的微观组织及质量控制进行了研究、分析，提出了一种高强度、抗疲劳、超细铜合金导电线材及其生产工艺。     

热输入对高强度气体保护焊丝焊缝金属强韧性的影响

采用拉伸、冲击试验和显微组织观察,研究了热输入在10~27 kJ/cm时对超低碳气体保护焊丝焊缝金属强度、韧性及显微组织的影响。结果表明,随着焊接热输入的增加,焊缝金属的强度和韧性呈下降趋势,其原因在于,随热输入的提高,合金元素烧损增多,焊缝冷却时间延长,焊缝金属高温再热区中强度较低、韧性较差的铁素体含量增加。     

Structure and properties of AA3003 alloy produced by accumulative roll bonding process

The investigation of the microstructure and mechanical properties has been conducted on AA3003 alloy produced by a novel intense plastic straining process named accumulativev roll-bonding (ARB). The results show that ultra-fine grained 3003 alloy having mean grain size of 700–800 nm was successfully produced by the 250°C-ARB. The average grain sizes of 250°C-ARB samples were reduced greatly from about 10.2 m initially to 700–800 nm. After 6 cycles of ARB, the whole volume of the material was filled with ultra-fine grains with high angle boundaries. The tensile strength of the ARB processed 3003 alloy (after 6 cycles) is considerably higher than that of the initial material, and about 1.5 times higher than that of commercially available fully-hardened (H18) 3003 alloy. Strengthening in ARB processed 3003 alloy may be attributed to strain hardening and grain refinement hardening.     

The improvement of strength and ductility in ultra-fine grained 5052 Al alloy by cryogenic- and warm-rolling

The effects of deformation temperatures and post-deformation annealing on mechanical properties, in conjunction with microstructural evolution in the 5052 Al alloy, were investigated. The combination of cryogenic-rolling with warm-rolling effectively increased tensile strength and yield strength without the decrease of ductility through the formation of ultra-fine grains with dynamic recovery in the 5052 Al alloy. And static annealing, as a post-heat treatment, enhanced the ductility. Therefore, ultra-fine grained 5052 Al alloy with high strength and a moderate level of ductility could be made by the combination of cryogenic-rolling with warm-rolling and the additional static annealing process.     

Improving Short-Circuit Current Capacity, Resistance, and Breaking Load of OPGW Constructions by Modifying Aluminium Alloy With AlB2

This article presents a method that can be applied to molten AA-6101 alloy to improve electrical properties of the aluminium part of the optical ground wire (OPGW) used in overhead transmission lines to protect phase conductors from lightning strike and to transmit signals and data. AA-6101 alloy in casting of the log as 6 m length and 178 mm diameter for extrusion has been inoculated by AlB₂ to decrease detrimental effects of Cr, Ti, V, and Zr on the conductivity of the material. After inoculation, improved billets were extruded as 9.5 mm diameter feedstock. Required wires drawn from the feedstock according to the construction types of OPGW to be tested were exposed to aging at 175°C, 6 h (T-8). Upon completion of the back-twist and performing-type stranding process, resistance, and short-circuit current capacity and breaking load of the OPGW 88/44 constructions with other metal combinations have been examined and tested to show improvement. Results are summarized in tables and graphically.     

新型Al-12．7Si-0．7Mg焊丝及其熔敷金属组织与性能研究

借助OM、SEM、TEM和拉伸实验机,研究了新型Al-12．7Si—0．7Mg焊丝及其熔敷金属的组织和性能,结果表明：密集排布的针片状Si相经热挤压和连续冷拉拔后破碎为细小颗粒并弥散分布,当拉拔变形量为77％时,焊丝的组织和拉伸性能较优,经固溶和时效热处理后焊丝熔敷金属拉伸性能显著提高,Al-12．7Si—0．7Mg焊丝合金可热处理强化。     

Optimization of material removal rate and surface roughness during electric discharge machining of ultra-fine grained Al6082 using Taguchi technique

In the current work, the statistical analysis of various electric discharge machining parameters on Al6082 ultra-fine grained aluminium alloy using Taguchi method has been presented. Repetitive corrugation and straightening (RCS) method was employed to obtain ultra-fine grained aluminium alloy. The electric discharge machining studies were carried out for test variables – pulse off time, pulse on time and current (I). The specimens were machined in dielectric medium with current range of 3 A to 9 A in step of 3 A. Machining features of the samples analysed statistically by adopting the Taguchi's - design of experiments (DOE) methodology. Impact of parameters on material removal rate (MRR) and surface roughness (SR) were examined via signal-to-noise ratio (S/N ratio, expressed in decibel, dB) as well as analysis-of-variance (ANOVA). Outcomes disclose that every selected response explicitly surface roughness (SR) and material removal rate was significantly influenced by parameters. The material removal rate was found to rise with discharge current and decrease with the duration of pulse on time and the duration of pulse off time. On the other hand, the surface roughness increased with increase in peak current and decreased with pulse on time and pulse off time especially. The machining mechanisms were examined by scanning electron microscopy.     

电脉冲空化制备超细镍磷粉体材料的理论与实验研究

本文从热力学和动力学角度分析了利用电脉冲空化制备超细镍磷粉体材料的可能性,并从实验上成功制备出粒径可控的镍磷合金粉体材料,研究结果表明电脉冲空化制备镍磷合金粉体材料的形核与长大过程主要受脉冲能量、脉冲方式、反应时间等多重因素控制.反应初期(60秒以内),反应形核受脉冲能量控制,镍磷合金粉体颗粒数随脉冲放电能量(包括脉冲电压和脉冲次数)的增加而增加;随反应时间延长(超过60秒),脉冲空化导致镍磷非晶合金粉体的反应被激活,溶液中镍磷粉体可自发形核、生长,直至反应完成.