应变时效对微合金钢显微组织结构的影响

研究了微合金钢应变时效处理前后的显微组织结构。结果表明,组织为铁素体和珠光体,铁素体呈板条形状。微合金元素的碳氮化物主要分布于晶内,少量分布于晶界上,晶内析出相尺寸远小于晶界析出相。析出物形状有圆形以及短棒形,尺寸由几纳米左右到几百纳米不等。时效后仅发现C原子在位错线附近偏聚,微合金元素在时效前对微量N元素绑定作用导致N原子未能参与Cottrell气团形成。     

微量合金成分对钢的高温变形抗力的影响

微量合金成分对钢的高温变形抗力的影响［日］长崎千裕等１前言关于碳素钢奥氏体温度区的变形抗力如何随碳含量而变化的问题，作者等在１９８８年报告了在大范围内改变温度和变形速度时的测定结果［１］。但１９９４年又发表了重新处理这一问题的另外的论文［２］。因此，...     

高温时效对等离子喷涂ZrO2涂层结构的影响

本文研究了等离子喷涂全稳定ZrO_2(MgO)涂层的相结构、显微组织、硬度、Mg元素分布及其与使用温度和时间的关系。结果表明,900℃时效6h而后随炉冷却的试样,相结构无明显变化,涂层的致密度增加,晶界的二次裂纹不明显,MgO未出现偏聚,涂层的硬度值最高;但当时效时间延长到2000h后,涂层表面则出现龟裂和疏松粉化现象。XRD分析发现,C—ZrO_2大部分转变为M—ZrO_2。SEM测定结果表明,二次裂纹主要是沿晶的;当处理温度为1100℃、时效6h时,MgO出现偏聚,相结构发生变化,涂层的晶面间距增加,硬度值降低。     

时效对TMC-2复合材料性能的影响

研究了时效制度对原位生成稀土钕氧化物颗粒增强Ti-6Al-4Sn-3.5Zr-0.5Mo复合材料（简称为TMC-2）棒材的组织和性能的影响，结果表明，采用直接时效处理可以获得比较高的室温拉伸强度和很低的650℃蠕变性能，而采用1030℃/0.5h/AC 800℃/0.5h/AC 时效的热处理制度，材料具有较好的拉伸，持久，蠕变和热稳定性等力学性能，时效温度升高，拉伸强度降低，而拉伸塑性，蠕变抗力和热稳定性有所改善。     

变形方式对深冲钢S20A时效冲击性能的影响

1.前言用于制造弹体和药筒的S20A优质碳素钢,按标准规定须作时效冲击检验,即将试样毛坯在调质状态下,经过10%的“拉或压”变形,再进行250℃时效处理,然后加工成冲击试样进行冲击试验。“拉或压”变形,可以有三种变形方式:“轴向拉伸变形”,“轴向压缩变     

时效温度对马氏体时效不锈钢延迟断裂行为的影响

借助于缺口慢拉伸试验研究了马氏体时效不锈钢延迟断裂倾向对时效温度的敏感性。研究结果表明,正常冶炼和加工的材料氢的质量分数在2×10-6以下,420和440℃欠时效处理的试样仍发生氢致延迟断裂;而460℃以上时效的缺口试样慢拉伸(0.001 5mm/min)的抗拉强度和断裂行为类似于快拉伸(0.15mm/min),即不发生延迟断裂。     

钒对Si-Mn系弹簧钢松弛抗力的影响

采用包辛格试验方法和透射电镜研究了0.01%～0.22%V对870～900℃正火,900～920℃淬火,400～460℃回火Si-Mn弹簧钢(%:0.34～0.53C、1.06～1.24Si、1.17～1.36Mn)的松弛抗力、力学性能和析出相的影响。结果表明,在870～920℃随奥氏体化温度增加,钢的强度增加;添加钒能增加钢的滞后环面积和钢的松弛抗力;钢中较合适的钒含量为0.05%～0.10%,含钒钢中有明显第二相粒子析出,0.06%V钢中析出第二相粒子细小。     

预时效对汽车用6082合金性能的影响

采用拉伸试验机、扫描电镜、EDS等分析手段,研究不同预时效制度对6082合金挤压材性能的影响.结果表明,在室温下停放28d,未预时效试样强度提高35MPa左右,而预时效处理后室温停放性能变化不大;室温停放后进行人工时效处理,未预时效试样强度最低,经180℃×5min预时效的试样强度最高.DSC结果显示室温下长时间放置,...     

Load Resistance Factor Design of Axially Loaded Pile Based on Load Test Results

The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations, considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form “t-z” method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation.     

Influence of Normal Load, Sliding Speed and Ambient Temperature on Wear Resistance of ZG42CrMo

 Abstract： To investigate the wear resistance of ZG42CrMo in industrial application, the wear behaviors under different normal loads, sliding speeds and ambient temperatures were simulated by an MMU-5G abrasion tester to acquire the friction coefficients and wear rates, with the morphology of worn surface observed by scanning electron microscopy (SEM) and chemical composition of worn surface and debris analyzed by X-ray energy dispersive spectroscopy (EDS). Combine with the theory of tribology, finally the regular of environmental factors′ influence on material wear behaviors is determined. The results show that the increase of load decreases wear resistance significantly, when the pressure reaches a certain extent, severe spalling occurs on the worn surface; the changes of speed result in the changes of size of abrasive debris, and then effect the wear behaviors, in the increasing process of speed, the wear rate increases firstly and then decreases; the rise of temperature causes changes in wear mechanism, bring forth oxidation film on the worn surface, which leads to significant improvement of the wear resistance of materials under high temperature compared to that under low temperature.     

金红石型纳米TiO2在HIPS塑料中的抗老化应用研究

采用金红石型纳米TiO2改性HIPS塑料,SEM及FTIR分析表明,通过表面改性可将低分子有机物接枝到纳米TiO2表面,并提高了无机纳米粒子在HIPS树脂中的相容性和分散性.金红石型纳米TiO2复合改性HIPS经过28d的氙灯气候加速老化后,其力学性能在较长时间内得到保持,抗色变能力大幅度提高,分子链断裂得到有效抑制.FTIR分析老化机理表明,由于纳米TiO2与光稳定剂的协同作用使改性HIPS的光老化速度得到有效抑制,其羰基和羟基吸收峰的振动特征在28 d的老化期间内均未发生明显变化.     

Effect of Structural Anisotropy on Contact Properties in a Silver - Graphite Composite

We have studied the effect of structural anisotropy on the contact properties of silver –5 mass% graphite composite. We have established that the highest erosion resistance is typical of contacts with a structure in which the flake-shaped graphite particles are located perpendicular to the working surface. Welding resistance is higher in contacts with a structure in which the graphite particles are located parallel to the working surface of the contact. We have shown that for any arrangement of the graphite particles in the silver matrix, contacts with an anisotropic structure made from bars obtained by extrusion are distinguished by a higher erosion resistance compared with contacts prepared by single pressing - sintering - final pressing - annealing. The results obtained are of practical importance for designing electrical contacts to be used in low-voltage automatic switches. They make it possible to improve the operating characteristics of silver - graphite composite materials.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 101–105, January–February, 2005.     

包钢提高货车静载重的实践与探索

文章阐述了包钢目前货车静载重的现状,介绍了提高货车静载重的意义,对影响货车静载重的因素进行了详细分析。结合包钢目前的情况提出了相应改进措施的实践,为进一步提高货车静载重,节约运输资源提供了参考。     

Study of Load Modeling Technology on Hardware-in-the-Loop Simulator of Gun Servo System

A hardware-in-the-loop (HWIL) simulator for gun servo system is described in this paper, and its load modeling technologies, such as road spectrum model, sea wave model are studied. The simulation results show that the models can be used in HWIL and satisfy the requirements of hardware-in-the-loop simulator of gun servo system.     

加工工艺对稀土HSn62-1黄铜耐脱锌腐蚀性能的影响

采用脱锌腐蚀深度测量方法、恒电位测试方法和光学显微镜等分析方法,研究了不同的加工工艺对稀土HSn62—1黄铜的耐税锌腐蚀性能的影响。结果表明,冷轧态的黄铜,由于β相沿着冷加工方向分布,同时位错密度和残余应力的增加,导致了其耐脱锌腐蚀性能比热轧态的黄铜和铸造态的黄铜差。热轧态的黄铜,由于在热加工过程中发生了回复和再结晶,使得其耐蚀性和铸造态的相当。     

钢包底吹对钢液混匀时间和排渣面积的影响

通过实验室水力模型实验,研究了钢包底吹方式、气体流量对钢液混匀时间、液面排渣面积的影响。实验结果表明,采用双孔底吹方式可使钢液混匀时间缩短,液面排渣面积减少,为在生产中使用合理的钢包底吹方式以及控制气体流量,有效促进夹杂物去除及减少卷渣提供依据。     

基于改进场模型的中国中部地区城市影响范围研究

Due to unique advantages in clearly understanding the interrelationship between city and its hinterland, as well as city and city, the study of urban spheres of influence is be-coming highlight in regional research. This paper improves traditional field model from two aspects:the composite indicator and regional accessibility, in order to delineate urban spheres of influence more reasonably. Taking three years of central China as a case study,this paper investigates dynamic evolution of urban spheres of influence. Focusing on the evolution of spatial pattern, we abstract five types and its corresponding three stages theo-retically. Finally, recommendation of development has been made for each stage. This study undertakes certain exploration in the study of urban spheres of influence from the perspective of theory and practice, hoping to provide some references for the study in this field and other regional research.     

PS-PVD 热障涂层显微结构对耐侵蚀性能的影响研究

采用等离子喷涂物理气相沉积 ( PS-PVD ) 技术开展了热障涂层梯度结构调控研究，通过调整喷涂送粉速率， 在底部、中间和顶部沉积阶段制备了五种不同的热障涂层，对热障涂层的显微组织、粗糙度、孔隙率、耐熔盐腐 蚀和耐粒子冲蚀性能进行表征，阐明了显微结构变化对热障涂层耐侵蚀性能的影响。研究表明：送粉速率的变化 对PS-PVD热障涂层羽柱状结构的沉积有显著的影响，低送粉速率下，涂层底部结构比较致密，当送粉速率增大时， 由于粉末颗粒在喷涂过程气化不充分，未熔粒子增加，羽柱状顶部结构趋向致密结构转变，涂层顶部孔隙率下降， 表面粗糙度降低。送粉速率由底至顶梯度递增制备的涂层表现出较高的耐熔盐腐蚀性能和耐粒子冲蚀性能。