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1.
WC粉末X射线衍射的粒度效应   总被引:1,自引:0,他引:1  
用X射线衍射研究粒度 10 .86~ 0 .12 4μm系列WC粉末的粒度效应。随粒度变小 ,衍射线线形发生明显变化 ,从敏锐到极其漫散。亚微米级粒度的WC粉末谱线半高宽随粒度变细显著变化 ,半高宽是度量粒度效应的主要指标 ,而对于微米级粒度的粒度效应则可应用谱线背底宽度来衡量。极细和超细粒度WC粉末衍射谱线的2θ位置明显偏离平衡位置 ,这与临近纳米粒度有关。WC粉末衍射强度也随粒度产生明显变化 ,衍射强度随粒度变细的变化规律与半高宽的规律呈反转对应关系。应用WC粉末X射线衍射的粒度效应 ,尤其是谱线宽化的规律作为评定亚微米级WC粉末粒度尤其是极细和超细粒度 ,是有应用前景的。  相似文献   

2.
破碎产物粒度精准预测是实现选厂破碎粒度分布调节和控制的关键。基于落重试验和理论分析,对不同矿物破碎特性及其粒度分布预测模型展开研究。结果表明:矿物破碎产物粒度分布与矿物给料粒度、冲击破碎比能耗、破碎参数有关,Boltzmann-Growth方程能够较好地拟合出破碎产物粒度分布与冲击破碎比能耗、t10的回归关系,且在同样破碎比能耗下,破碎产物粒度越小,其累积效应越弱;不同矿物和不同粒度之间矿物破碎特性存在较大差异;在此基础上提出一种综合广义回归模型与粒子群算法的破碎粒度预测与优化模型,并通过试验验证模型的适用性和可靠性,可为矿物破碎粒度智能调控和优化提供理论基础。  相似文献   

3.
《硬质合金》2016,(5):311-321
本文研究了粒度接近的5个批次原料WC粉及对应合金的特性。利用扫描电镜分析原料WC粉的整体特征及WC颗粒聚集体构成特征,用激光粒度分析仪分析了各批次原料WC粉的粒度分布,用定量金相软件分析了合金成品WC晶粒粒度分布。结果表明,粒度接近的各批次的原料WC粉颗粒粒度分布不尽相同。在相同的球磨时间下,WC粉末粒度分布相同的批次,合金WC晶粒粒度分布曲线不尽相同,原料WC粉末中单晶WC颗粒的粒度对合金WC晶粒粒度分布有直接影响。评价WC的质量应从Fsss粒度、粒度分布、电镜形貌和球磨实验合金的晶粒分布进行综合分析。  相似文献   

4.
X射线小角散测量氮化铁磁性液体中颗粒的粒度   总被引:1,自引:0,他引:1  
通过X射线小角散射测定了氮经铁磁性液体中氮化铁纳米级磁性颗粒的粒度分布和平均粒度。通过和透射电镜检测得到的粒度结果进行比较,发现两者得到的检测数据误差不超过10%。由此可以证明X射线小角散射方法可以适用于磁性液体中纳米粉末的粒度分布和平均粒度测量。  相似文献   

5.
使用Malvern MS2000型激光粒度仪对M6/12和M8/16两种规格金刚石微粉的粒度组成进行了检测,通过不同实验室Malvern MS2000型激光粒度仪和不同型号的激光粒度仪对M0.5/1、M1/2、M6/12、M8/16、M20/30、M22/36六种规格金刚石微粉的粒度组成进行了对比检测.实验发现Malvern MS2000型激光粒度仪具有良好的检测重复性,且不同实验室Malvern MS2000型激光粒度仪的检测结果具有可对比性;Malvern MS2000型激光粒度仪与不同型号激光粒度仪之间检测结果的可对比性偏低;同厂家的各型号激光粒度仪检测结果之间的可对比性高于不同厂家激光粒度仪检测结果之间的可对比性.  相似文献   

6.
粉末粒度的测定是粉末冶金生产中检验粉末质量的重要依据。目前有几十种测定粉末粒度的方法,除筛分法和显微镜法之外,其他都是通过测定与粒度有关的粉末颗粒的物理、力学参数,再换算成平均粒度或粒度组成。本文介绍作者提出的一种新的粉末平均粒度电测法——Q值法。  相似文献   

7.
为了满足面向服务的空间数据框架对空间访问控制的需求,提出多粒度的时空相关访问控制模型MSTAC。此模型在基于角色的访问控制模型基础上,进行属性约束扩展。属性约束包括上下文时间属性、用户的位置属性、角色的时间属性约束、地图类的图层向量约束、图层的尺度及制图时间约束、地物要素间的拓扑约束、地物要素的语义属性约束以及要素视图的字段约束。通过此模型,授权用户将受控访问不同粒度的空间数据集。这些粒度包括地图粒度、图层粒度、要素对象粒度和要素视图粒度。最后,将MSTAC模型在web GIS中实施。该实例显示了在不同的数据粒度上和不同的时间段内,系统可以对不同粒度服务进行肯定和否定授权。  相似文献   

8.
序言粉末粒度的测定,是Al_2O_3生产和科研中经常测控的项目之一,尤其对于多品种氧化铝,其粒度大小和粒度组成,是至关重要的。它直接影响到产品的性能和用途。在生产和科研中,也常依中间产品粒度大小及其分布来改  相似文献   

9.
颗粒流滴注润滑是一种新型绿色切削润滑技术,能解决传统颗粒流切削的颗粒导入问题。为了研究颗粒粒度对切削效果的影响,进行45钢车削实验,用不同粒度的Al2O3颗粒流润滑,分析切削力、切削温度、光洁度、刀具寿命和粒度的关系。实验结果显示:粒度影响切削效果,存在最佳粒度,粒度过大或过小都会导致切削效果变差;粒度过大会影响颗粒流渗透进摩擦面,粒度过小则无法适应粗糙及剧烈变动的摩擦面,两者都限制了颗粒流的分离和抹平作用,导致减摩效果变差;采用合理粒度,颗粒流点滴润滑切削效果甚至好于浇注润滑。  相似文献   

10.
通过粒度衡算和质量衡算对氧化铝种分过程附聚段进行种分过程粒度变化模型的构建,选取合适的模型参数和动力学方程,应用模型计算某氧化铝厂种分附聚段出口粒度分布,并与实测值进行对比.结果表明:模型计算粒度分布与实测结果基本吻合,平均粒度的实验值与模型计算值误差在10%以内.  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

13.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

14.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

15.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。  相似文献   

16.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

17.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

18.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.  相似文献   

19.
A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.  相似文献   

20.
On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.  相似文献   

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