共查询到18条相似文献，搜索用时 250 毫秒
1.
Cu-Ag filamentary microcomposites with different Ag contents were prepared by cold drawing and intermediate heat treatments. The microstructure characterization and filamentary distribution were observed for two-phase alloys under different conditions. The effect of heavy drawing strain on the microstructure evolution of Cu-Ag alloys was investigated. The results show that the microstructure components consist of Cu dendrites, eutectic colonies and secondary Ag precipitates in the alloys containing 6%-24% （mass fraction） Ag. With the increase in Ag content, the eutectic colonies in the microstructure increase and gradually change into a continuous net-like distribution. The Cu dendrites, eutectic colonies and secondary Ag precipitates are elongated in an axial direction and developed into the composite filamentary structure during cold drawing deformation. The eutectic colonies tend to evolve into filamentary bundles. The filamentary diameters decrease with the increase in drawing strain degree for the two-phase alloys, in particular for the alloys with low Ag content. The reduction in filamentary diameters becomes slow once the drawing strain has exceeded a certain level. 相似文献
2.
The deformation behavior of hot isostatic pressing (HIP) FGH96 superalloy was characterized in the temperature range of 1 000-1 100℃and strain rate range of 0.001-0.1s-1 using hot compression testing. The flow curves of HIP FGH96 superalloy during hot deformation was analyzed systematically. The results show that deformation temperature, strain rate and strain are the main influence factors on flow stress of HIP FGH96 superalloy during hot deformation. The flow stress displays a peak at a critical strain and then decreases with further increase in strain. For a given strain, the flow stress decreases with the increase of deformation temperature, and increases with the increase of strain rate. A mathematical model of these flow curves was established through regression analysis and taking the strain as a modification factor. The calculated stress values agree well with the experimental values. 相似文献
3.
Junaidi Syarif Agung Iswadi Mariyam Jameelah Ghazali Zainuddin Sajuri Mohd Zaidi Omar 《浙江大学学报(A卷英文版)》2013,14(12):906-914
The effect of solute Cu and Cu precipitates on the wear behavior of ferritic iron under an unlubricated condition was investigated. The specific wear rate of Cu-containing steel abruptly decreased up to 50 N of load, and then gradually decreased with further increased load. The specific wear rate of the as-quenched specimen, in which Cu was in a solid solution, was the lowest among all the specimens at low loads, and all specimens had almost the same specific wear rate at high loads. Subsurface observation showed that the hardness increments of all specimens decreased with increased depth below the worn surface. The as-quenched specimen had a relatively large depth of deformed region than the other specimens even though the increments in hardness were almost the same for all specimens at low loads. With the same hardness at an unworn state, the as-quenched and over-aged specimens exhibited a substantial increase in hardness and large deformed regions below the worn surfaces. This finding indicated that the enhancement in plastic deformation and work hardening led to the decrease in the specific wear rate of the as-quenched specimen at low loads and the improvement in the wear resistance of all specimens at high loads. 相似文献
4.
Bearing capacity and load transfer mechanism of a static drill rooted nodular pile in soft soil areas 总被引：2，自引：0，他引：2
The static drill rooted nodular pile is a new type of pile foundation consisting of precast nodular pile and the surrounding cemented soil. This composite pile has a relatively high bearing capacity and the mud pollution will be largely reduced during the construction process by using this type of pile. In order to investigate the bearing capacity and load transfer mechanism of this pile, a group of experiments were conducted to provide a comparison between this new pile and the bored pile. The axial force ofa precast nodular pile was also measured by the strain gauges installed on the pile to analyze the distribution of the axial force of the nodular pile and the skin friction supported by the surrounding soil, then 3D models were built by using the ABAQUS finite element program to investigate the load transfer mechanism of this composite pile in detail. By combining the results of field tests and the finite element method, the outcome showed that the bearing capacity of a static drill rooted nodular pile is higher than the bored pile, and that this composite pile will form a double stress dispersion system which will not only confirm the strength of the pile, but also make the skin friction to be fully mobilized. The settlement of this composite pile is mainly controlled by the precast nodular pile; meanwhile, the nodular pile and the surrounding cemented soil can be considered as deformation compatibility during the loading process. The nodes on the nodular pile play an important role during the load transfer process, the shear strength of the interface between the cemented soil and the soil of the static drill rooted pile is larger than that of the bored pile. 相似文献
5.
The western Iratsu mass, the largest tectonic body in the Sambagawa metamorphic belt, central Shikoku, is mainly composed of epidote amphibolite with minor amounts of eclogite. Systematically, a majority of garnets show bell-shaped chemical zoning of pyrope contents and Mg/(Mg Fe2 ) monotonously increasing outward. The grossular component in zonal garnet increases outwards, maximizes at an intermediate part, and then decreases towards the outermost rim, reflecting a process from increasing to decreasing pressure conditions during the prograde metamorphism. Jadeite contents of omphacite range from 25～20mole% within the cores to 15～10 mole% at the rims, implying a pressure-decreasing process (from 11 × 105 Pa to 8 × 105 Pa). The peak pressure-temperature (P-T) condition of 630～680 ℃ and ca. 15× 105 Pa in the western Iratsu mass is much higher than that of (610±25) ℃ and (10± 1)× 105 Pa of the Sambagawa oligoclase-biotite zone schists. The authors suggest a clockwise P-T-t path for the western Iratsu mass. 相似文献
6.
Progressive failure analysis of slope with strain-softening behaviour based on strength reduction method 总被引：1，自引：0，他引：1
Based on the strength reduction method and strain-softening model,a method for progressive failure analysis of strain-softening slopes was presented in this paper.The mutation is more pronounced in strain-softening analysis,and the mutation of displacement at slope crest was taken as critical failure criterion.An engineering example was provided to demonstrate the validity of the present method.This method was applied to a cut slope in an industry site.The results are as follows:(1) The factor of safety and the critical slip surface obtained by the present method are between those by peak and residual strength.The analysis with peak strength would lead to non-conservative results,but that with residual strength tends to be overly conservative.(2) The thickness of the shear zone considering strain-softening behaviour is narrower than that with non-softening analysis.(3) The failure of slope is the process of the initiation,propagation and connection of potential failure surface.The strength parameters are mobilized to a non-uniform degree while progressive failure occurs in the slope.(4) The factor of safety increases with the increase of residual shear strain threshold and elastic modulus.The failure mode of slope changes from shallow slip to deep slip.Poisson’s ratio and dilation angle have little effect on the results. 相似文献
7.
An improved configuration of the membrane stack was adopted in the electrodeionization （EDI） cell to prevent precipitation of bivalent metal hydroxide during the running. The operational parameters that influenced the removal of copper ions from the dilute solution were optimized. The result showed that a moderate decrease in the inlet pH value and a moderate increase in the applied voltage could achieve a better removal effect. The steady process of electroplating wastewater treatment could be achieved with a removal efficiency of more than 99.5% and an enrichment factor of 5-14. The concentration of copper in purified water was less than 0.23 mg/L. This demonstrated the applicability of recovering heavy metal ions and purified water from electroplating effluent for industrial reuse. 相似文献
8.
The failure behavior of diamond-coated die was investigated experimentally and analytically through finite element method (FEM) simulation in the present work. Diamond coatings were fabricated by straight hot filament chemical vapor deposition (CVD) passing through the interior hole of the drawing die using a mixture of hydrogen and acetone as source gases. The performance tests were made under real drawing condition. Scanning electron microscopy (SEM) was used for the study of coating wear after die service. The coating wear appears on two regions of the reduction zone: one is near the entrance where the contact begins, and the other is at the end of the reduction zone. FEM simulation was made for calculating the von Mises stresses distribution on the coating and substrate during the drawing process. The present work was of great practical significance for the improvement of drawing performance of diamond-coated drawing dies. 相似文献
9.
This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers, the confining pressure and the type of geotextile. Modeling was performed on samples with five different diameters： 38, 100, 200, 500 and 600 mm. The elastic-plastic Mohr-Coulomb model was used to simulate sand behavior. Results showed that small-sized samples show higher values of peak strength and higher axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect on the mechanical behavior of reinforced sand decreases with an increase in the sample size. 相似文献
10.
In this study, a simple roller burnishing tool was made to operate burnishing processes on A356/5%SIC metal matrix composite fabricated by electromagnetic stir casting under different parameters. The effects of burnishing speed, burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured. Scanning electron microscopy （SEM） graphs of the machined surface with PCD （insert-10） tool and roller burnished surface with tungsten carbide （WC） roller were taken into consider- ation to observe the surface finish of metal matrix composites. The mechanical properties （tensile strength, hardness, duc- tility） of A356/5%SIC metal matrix composites were studied for both unburnished samples and burnished samples. The results revealed that the roller burnished samples of A356/ 5%SIC led to the improvement in tensile strength, hardness and ductility. In order to find out the effects of roller bur- nishing process parameters on the surface roughness of A356/ 5%SIC metal matrix composite, response surface methodol- ogy （RSM） （Box-Behnken design） was used and a prediction model was developed relevant to average surface roughness using experimental data. In the range of process parameters, the result shows that roller burnishing speed increases, and surface roughness decreases, but on the other hand roller burnishing force and number of passes increase, and surface roughness increases. Optimum values of burnishing speed （1.5 m/s）, burnishing force （50 N） and number of passes （2） during roller burnishing of A356/5%SIC metal matrix com- posite to minimize the surface roughness （predicted 1.232 μm） have been found out. There was only 5.03% error in the experimental and modeled results of surface roughness. 相似文献
11.
范韵敏 《Journal of Zhangzhou Technical Institute》2012,14(2):20-25
通过盐析透析、离了层析、疏水层析,对链霉菌属发酵液中的阿魏酸酯酶（FAE）进行分离纯化。并进行酶学性质研究。得出的阿魏酸酯酶的纯化倍数为2．67,回收率为55．8％,酶分子约为30kDa。其最适反应pH约为6．0,最适温度约为50℃,金属离子Cu^2＋和Zn^2＋对阿魏酸酯酶酶活力均有明显的抑制作用,而Mg^2＋、Fe^2＋、Ca^2＋、Na^＋和Mn^2＋对酶的活性均有一定的促进作用。 相似文献
12.
基于Gleeble-3500热模拟试验机平台,对6061铝合金进行等温热压缩实验,研究了该合金在变形温度为350~500℃和应变速率为0.01~10s-1条件下的高温流变行为并建立了6061铝合金的Arrhenius本构方程,应用于Deform软件进行热压缩实验模拟基于动态材料模型和Murty准则,建立了6061铝合金在不同应变下的加工图,结合显微组织进行验证。结果表明,该合金材料的流变应力随应变速率增加而增大,随变形温度降低而增大建立的本构方程能较好描述该合金的高温流变行为变形温度为460~500℃,应变速率为0.1~0.5s-1的区域是该合金最佳工艺参数范围。 相似文献
13.
14.
以自制硅酸钙（CaSiO3）和羟基磷灰石（HAP）超细粉体为原料,按照不同的比例混合、成型、煅烧制得CaSiO3-HAP复合生物陶瓷。采用X-射线衍射仪（XRD）和扫描电镜（SEM）对粉体及陶瓷样品进行物相成分和显微结构分析,并对复合生物陶瓷的收缩率、抗弯强度、断裂韧性和硬度等性能进行测定。研究结果表明：在HAP中添加一定量的CaSiO3,可以减小HAP陶瓷的收缩,并能提高其力学性能,CaSiO3含量为30wt％的CaSiO3-HAP复合生物陶瓷综合性能最佳,其抗弯强度和断裂韧性分别达到156．7MPa和2．32MPa·m^1/2,维氏硬度值达到6．5GPa,比纯HAP陶瓷的性能均有了较大的提高。 相似文献
15.
试验研究了热处理对CuCr/1Cr18Ni9Ti双金属复合材料结合区组织和性能的影响。结果表明,热处理后,结合区没有明显的裂纹和脆化现象,界面反应层宽度无明显增加;热处理工艺明显提高了1Cr18Ni9Ti奥氏体不锈钢的硬度,界面反应层和CuCr合金的显微硬度略有增加。 相似文献
16.
研究了Al-1Mn-1Mg合金不同变形下的流变应力曲线和微观结构特征,探讨了该铝材在热变形过程中的动态软化行为.结果表明,应变速率为0.1 s-1时,若变形温度较低,则发生了动态回复;若变形温度高于723 K,产生明显的动态再结晶;变形温度为673 K时,在低应变速率条件下,产生动态再结晶,应变速率高于0.1s-1,软化过程具有动态回复和动态再结晶的混合特征.当应变速率高于5.0s-1时,产生几何动态再结晶. 相似文献
17.
为了探索新的稻草利用途径,开发一种基于稻草的环保复合材料,对羧甲基纤维素与稻草的热压复合进行了研究。将稻草进行短切,以水为混合及复合助剂,先使羧甲基纤维素与稻草在常温常压下进行混合,然后在热压机上进行加热加压复合。研究了羧甲基纤维素用量、热压温度、热压时间对复合材料拉伸力学性能及硬度的影响。结果表明,复合材料的拉伸强度随羧甲基纤维素的用量的增加而增加,随热压时间及热压温度的增加先增加后减小,在羧甲基纤维素用量50%,热压温度120℃,热压时间10 min时,复合材料的拉伸强度为1.52 MPa。复合材料的硬度受加工条件的影响较小。 相似文献
18.
研究了橡塑比、过氧化物复合硫化体系及KH-570硅烷偶联剂对动态硫化EPDM/PP/SiO2共混物的力学性能的影响.结果表明,随着PP含量的增加.动态硫化EPDM/PP/SiO2共混物的力学性能和硬度增加,但压缩永久变形增加,断裂伸长率却减小.过氧化物复合硫化体系中,当DCP为1.5份时,动态硫化EPDM/PP/SiO2共混物的综合物理力学性能较好.加入KH-570改性的白炭黑,对EPDM/PP/SiO2共混物起到补强的作用;且提高共混物的交联密度,降低压缩永久变形. 相似文献