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1.
The tensile elastic modulus (E), yield stress (σY) and microhardness (MH) of neat and binary and ternary blends of glassy semicrystalline ethylene–vinyl alcohol copolymer (EVOH), a glassy amorphous polyamide and a semicrystalline nylon‐containing ionomer covering a broad range of properties were examined. The tests were carried out on dry and water‐equilibrated samples to produce stiffer and softer materials, respectively. From the results, more accurate linear correlations were found to describe adequately the microhardness, modulus and yield stress of these strongly self‐associated polymers through hydrogen bonding. Copyright © 2003 Society of Chemical Industry 相似文献
2.
Microhardness measurements have been performed on untreated (virgin) and electrically stressed, solvent‐cast laboratory‐prepared samples of pure poly(phenylene oxide) (PPO), pure polystyrene (PS), and PPO : PS polyblends with different weight proportions. Results of such measurement on untreated polyblend sample show that microhardness (Hv) increases with increase in the content of PS up to 10 wt %, which attributed to the existence of homogeneous phase morphology. However, this feature is not observable in samples containing higher content of PS. Electrical stress is found to modify considerably the mechanical property of polymer. The effect of electric field on the microhardness of such samples (PPO : PS :: 90 : 10) has been characterized by the existence of a peak. Trapping of charge carriers in electrically stressed samples imparts hardening to the polyblend up to an applied step field of 190 kV/cm. However, the excessive charging beyond this step field value destroys this characteristic. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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采用多弧离子镀设备,在高速钢W18Cr4V上先进行等离子氮化,再沉积TiN薄膜,研究了不同渗氮温度和时间对PN+TiN薄膜组织和性能的影响。结果表明,温度为500℃左右和时间为2h以上条件下对W18Cr4V进行渗氮处理后再沉积TiN薄膜,可以得到最佳的薄膜表面显微硬度(1800~2000HV0.05)和膜/基结合力(50N),涂层耐磨性也得到明显提高。 相似文献
5.
运用电沉积的方法在45钢基体上制备Ni-P合金镀层,使用差示扫描量热法(DSC)和热重法(TG)分析非晶态NiP合金镀层在20℃/min加热速率下的热效应和质量变化。在300℃和400℃分别对镀层进行0,15,30,45,60,75min的热处理,采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、显微硬度计对镀层进行表征。结果表明:Ni-P合金镀层在加热过程中的放热峰出现在284.8℃处,镀层的质量和元素组成稳定;晶化过程经历了非晶态、亚稳态NiP和Ni5P2、稳定态Ni3P的转变;经过热处理后,镀层的显微硬度显著提高,最大值达1036.56HV,约为镀态的2倍;热处理态镀层的耐NaCl溶液腐蚀性能比镀态有所下降,但两者都比45钢基体好。 相似文献
6.
The nanoindenting method is based on the automatic measurement and recording of the force acting on the indenter (10−2-5 N) and the depth of indentation (10−2-200 μm). The scratch hardness or nanoscratching method is based on the continuous recording of resistance forces to movement
of the indenter impressed into the surface.
__________
Translated from Problemy Prochnosti, No. 4, pp. 132–139, July–August, 2006. 相似文献
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8.
An Investigation of Microstructure and Microhardness
of Sn-Cu and Sn-Ag Solders as Functions of Alloy Composition and Cooling Rate 总被引:1,自引:0,他引:1
Sun-Kyoung Seo Sung K. Kang Da-Yuan Shih Hyuck Mo Lee 《Journal of Electronic Materials》2009,38(2):257-265
The microstructure and microhardness of Sn-xAg and Sn-xCu solders were investigated as functions of alloy composition and cooling rate. The Ag compositions examined varied from
0.5 wt.% to 3.5 wt.%, while Cu varied from 0.5 wt.% to 2.0 wt.%. Three cooling rates were employed during solidification:
0.02°C/s (furnace cooling), about 10°C/s (air cooling), and 100°C/s or higher (rapid solidification). Sn grain size and orientation
were observed by cross-polarization light microscopy and electron-backscattering diffraction (EBSD) techniques. The microhardness
was measured to correlate the mechanical properties with alloy compositions and cooling rates. From this study, it was found
that both alloy composition and cooling rate can significantly affect the Sn grain size and hardness in Sn-rich solders. The
critical factors that affect the microstructure–property relationships of Sn-rich solders are discussed, including grain size,
crystal orientation, dendrite cells, twin boundaries, and intermetallic compounds (IMC). 相似文献
9.
薄板模具钢脉冲Nd:YAG激光熔凝区显微硬度特征的影响因素 总被引:1,自引:0,他引:1
本文在厚度为 0 .5— 2 .0mm的 5Cr4Mo3SiMnVAl(0 12Al)模具钢和Cr12MoV模具钢薄板上 ,采用脉冲Nd :YAG激光进行了激光熔凝实验 ,研究了工艺参数 (脉冲宽度和脉冲频率 )、材质和材料厚度对激光熔凝后熔凝层显微硬度特征的影响。结果表明 :随着脉冲宽度的增加或脉冲频率的减少 ,激光熔凝区的显微硬度有减少的趋势 ;Cr12MoV模具钢的激光熔凝区的显微硬度比 0 12Al模具钢的低 ;随着材料厚度的增加 ,激光熔凝区的显微硬度表现为先增加后减少的趋势。激光熔凝工艺参数、材料的热扩散情况和材料的热物性参数的不同是造成上述现象的主要原因。 相似文献
10.
等离子喷涂Al2O3+13wt%TiO2陶瓷涂层的 激光重熔处理 总被引:5,自引:0,他引:5
本文用X射线衍射、扫描电镜和显微硬度研究了等离子喷涂Al2O3+13wt%TiO2陶瓷涂层激光重熔处理后陶瓷熔化层的组织结构及硬度变化特征。激光重熔区亚稳相Y-Al2O3转变成为稳定相α-Al2O3:TiO2与Al2O3反应生成TiAl2O3陶瓷熔化层致密,无孔隙、少裂纹或无裂纹;熔化层硬度有较大提高,且随激光能量密度的增大而增大,而涂层设计对其影响很小。此外,激光重熔能极大地提高陶瓷的涂层的耐磨 相似文献