首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   102篇
  免费   1篇
  国内免费   3篇
综合类   2篇
化学工业   12篇
金属工艺   47篇
机械仪表   6篇
建筑科学   1篇
能源动力   2篇
无线电   1篇
一般工业技术   31篇
冶金工业   2篇
原子能技术   1篇
自动化技术   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   7篇
  2016年   6篇
  2015年   5篇
  2014年   5篇
  2013年   5篇
  2012年   7篇
  2011年   6篇
  2010年   7篇
  2009年   11篇
  2008年   9篇
  2007年   12篇
  2006年   4篇
  2005年   1篇
  2004年   6篇
  2002年   2篇
  2000年   2篇
  1997年   1篇
  1993年   1篇
  1992年   1篇
排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
A new hot-dip galvanizing method was employed on hot-rolled low carbon steel. The effects of Al contents on microstructure, micro-hardness and corrosion resistance of Zn-Al alloy coatings were systematically investigated. Phase composition, microstructure and element distribution in Zn-Al alloy coatings were analyzed using X-ray diffraction (XRD) and electron probe micro analysis (EPMA), respectively. It is found that Al content (0. 6–6. 0 wt. %) in galvanizing zinc affects surface quality and adhesion between coatings and matrix in the newly developed method. In addition, with increasing Al content, micro-hardness significantly increased due to the increase in Zn-Al eutectoid phases. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) also revealed that increase in Al plays a noticeable role in improving the corrosion resistance of Zn-Al alloy coatings.  相似文献   
2.
A comparative study of micro-structural transformations and tribological properties of the friction stir processed AZ91-D magnesium (Mg) alloy in normal friction stir processing (NFSP) and submerged friction stir processing (SFSP) conditions was carried out. The optimum parameters used for processing were tool rotational speed of 1000?rpm/min, 50?mm/min of transverse speed and 6 numbers of passes. A significant reduction in grain size (28.7% and 13.1%) and increase in micro-hardness (14.55% and 8.92%) along depth and width of stir zone (SZ) of SFSPed specimen has been achieved as compared to NFSPed specimens. This change can be attributed to the dynamic recrystallisation and removal of excess frictional heat leading to inhibited post-grain growth in the processed alloy. Pin-on-disc sliding wear testing was conducted to compare the wear performance of NFSPed and SFSPed specimens. The SFSPed specimen has shown an improved wear resistance as compared to NFSPed specimens. The major prevailing wear mechanisms were abrasion, delamination, oxidation and mild plastic deformation.  相似文献   
3.
Ti-6Al-4V is widely used in aerospace, biomedical applications and in many corrosive environments. However, titanium alloy has low hardness and poor wear resistance. This paper introduces a machining method of SiC abrasive-mixed electrical discharge machining (EDM) with magnetic stirring. Structural features and chemical composition were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Micro-hardness distribution on the cross section was measured with an FM800 micro-hardness tester. The influence of pulse width and pulse peak current on the formation of the surface hardening layer is analyzed. The results show that a continuous strengthened layer was formed during the SiC abrasive-mixed EDM process. The hardness of the formed layer was significantly improved because of the formation of TiC and TiSi2 phases on the machined surface. With the increase of pulse width, the thickness of the strengthened layer increases and the quality becomes better.  相似文献   
4.
通过扩散渗法在DZ125合金表面制备了Ce-Y联合改性铝化物渗层,分析了共渗层的结构及相组成,并对其组织形成机理和抗冲蚀性能进行了研究。结果表明:1000℃/2 h下所制备的Al-Ce-Y共渗层具有多层结构,由外向内依次为Ni Al和少量Al_3Ni_2组成的外层,Al_3Ni_2内层及富Al的互扩散层,Ce、Y元素主要集中在共渗层的外层,起到细化晶粒及促渗的作用。固体粒子冲蚀结果表明:Al-Ce-Y共渗显著的提高了DZ125合金在小攻角下的抗固体粒子冲蚀性能,冲蚀机理为犁削和切削损伤;随着攻角的增大,Al-Ce-Y共渗层的冲蚀率逐渐增大,冲蚀机理向脆性断裂和疲劳破坏转变,当攻角为90o时,其冲蚀率高于DZ125基体。  相似文献   
5.
In this study, the case properties and diffusion kinetics of AISI 440C and AISI 52100 steels borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2, 4 and 8 h.The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B and CrB compounds.The thickness of boride layer increases by increasing boriding time and temperature for all steels. The hardness of the boride compounds formed on the surface of steels AISI 52100 and AISI 440C ranged from 1530 to 2170 HV0.05 and 1620 to 1989 HV0.05, respectively whereas Vickers hardness values of untreated steels AISI 440C and AISI 52100 were 400 HV0.05 and 311 HV0.05, respectively. The activation energies (Q) of borided steels were 340.426 kJ/mol for AISI 440C and 269.638 kJ/mol for AISI 52100. The growth kinetics of the boride layers forming on the AISI 440C and AISI 52100 steels and thickness of boride layers were also investigated.  相似文献   
6.
李红霞  郭卫  王自强  张红霞 《玻璃》2013,40(1):38-40
利用普通Na2O-CaO-SiO2玻璃体系,通过调整CaO/MgO摩尔比,针对太阳能电池用封装玻璃组分的性能,研究了不同CaO/MgO摩尔比对玻璃软化温度、转变温度、膨胀系数及高低温黏度的影响规律,探讨了不同CaO/MgO摩尔比值对玻璃力学性能的影响。  相似文献   
7.
Micro-hardness testing is widely used to measure the materials local response and is very valuable to describe gradients of physical properties. For polymers, the most common use is to measure a scalar value (hardness or modulus), which gives access to useful qualitative information but can clearly not be used to identify local constitutive models, strongly needed to achieve the numerical simulation of heterogeneous massive parts. In this study, load/displacement curves obtained at a micro-scale are used to identify the parameters of an Edwards-Vilgis hyperelastic model. The protocol proposed is coupling FE simulations achieved with Abaqus and optimization procedures using the dedicated software Boss Quattro. In order to limit the microstructure and viscous effects, the material studied is an unfilled natural rubber which exhibits a behavior very close to perfect hyperelasticity. Several numerical parameters (indent geometry, friction, thickness, …) as well as experimental protocols were tested in order to check the protocol reliability. The identified parameters are used to simulate macroscopic tests (tensile, compression and pure shear tests). The agreement with experimental data is very good, which is rarely found in the literature and which validates several numerical assumptions.  相似文献   
8.
氧化钛含量对氧化铝基涂层磨损性能和机制的影响   总被引:1,自引:0,他引:1  
研究了TiO2含量对大气等离子喷涂Al2O3基涂层的晶体结构组成相、显微硬度、摩擦磨损性能和磨损机制的影响.选用重量百分比为0,13%,40%这3种TiO2含量参量,即纯A12O3,AI2O3-13%(wt)TiO2和AI2O3-40%(wt)TiO2陶瓷涂层.采用XRD分析涂层的晶体结构组成相,Vickers显微硬度计评价显微硬度.采用SRV摩擦磨损试验机,通过AISI52100钢球和A12O3陶瓷球2种材料本质差异甚大的对摩副,在干摩擦条件下评价涂层的摩擦磨损性能,并通过扫描电镜观察涂层磨损机制.结果表明,Al2O3基涂层的显微硬度随TiO2含量增加而降低;A12O3基涂层皆显示出抗磨性能随TiO2含量增加而降低,而与对摩副材质无关.涂层中含有TiO2无益于提高Al2O3基涂层的摩擦磨损性能.  相似文献   
9.
The interfacial bonding between layers in ultrasonically consolidated structures is poor for some material combinations, resulting in relatively low bond strength. This makes resultant parts unsuitable for structural applications. This work discusses a study of the effects of post process heat treatment of ultrasonically consolidated commercially pure titanium and aluminum alloy 3003 dual-material systems. The lap shear strengths of as-consolidated specimens as well as heat treated ones were tested. The results show that there is significant improvement of the strengths of post processed specimens over the as-consolidated ones. The improvement is as a result of stress relieving of the strain hardened interface between the two materials and some interactions of the base materials across the interfacial boundaries at elevated temperatures, leading to stronger bonds. The study highlights the role of post process heat treatments for improving the mechanical properties of ultrasonically consolidated structures.  相似文献   
10.
ZL104合金表面化学镀镍磷合金层的研究   总被引:5,自引:1,他引:4  
在ZL104合金表面上进行Ni-P与Ni-Cu-P化学镀,以提高ZL104合金材料的耐蚀性与耐磨性。结果表明:化学镀可以显著提高ZL104合金表面的硬度,并改善其在5%NaCl溶液中的耐蚀性;在200~520℃温度下热处理后,镀层的硬度显著提高,但耐蚀性略有降低,这可能与镀层中的析出物Ni3P析出有关。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号