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101.
NiTi形状记忆合金激光气体氮化层表面特征 总被引:2,自引:0,他引:2
为改善NiTi合金的表面性能,利用2kW连续波Nd:YAG对NiTi合金进行激光气体氮化处理。采用SEM、TEM、XRD、XPS和纳米压痕研究了氮化层的显微组织及表面特征.结果表明:激光气体氮化可以在NiTi合金表面制备连续、无裂纹、厚度为2μm的TiN表面层,该表面层中基本不合有Ni元素且具有很高的硬度,其纳米压痕硬度为29.28GPa. 相似文献
102.
103.
Jinhong Shin Wyatt A. Winkenwerder Kyriacos Agapiou Gyeong S. Hwang 《Thin solid films》2007,515(13):5298-5307
Chemical vapor deposition growth of amorphous ruthenium-phosphorus films on SiO2 containing ∼ 15% phosphorus is reported. cis-Ruthenium(II)dihydridotetrakis-(trimethylphosphine), cis-RuH2(PMe3)4 (Me = CH3) was used at growth temperatures ranging from 525 to 575 K. Both Ru and P are zero-valent. The films are metastable, becoming increasingly more polycrystalline upon annealing to 775 and 975 K. Surface studies illustrate that demethylation is quite efficient near 560 K. Precursor adsorption at 135 K or 210 K and heating reveal the precursor undergoes a complex decomposition process in which the hydride and trimethylphosphine ligands are lost at temperatures as low at 280 K. Phosphorus and its manner of incorporation appear responsible for the amorphous-like character. Molecular dynamics simulations are presented to suggest the local structure in the films and the causes for phosphorus stabilizing the amorphous phase. 相似文献
104.
The AlCoCrCuFeNi high-entropy alloy system was synthesized using a well-developed arc melting and casting method. Their elemental effect on microstructures and hardness was investigated with X-ray diffraction, scanning electron microscopy and Vickers hardness testing. The alloys exhibit quite simple FCC and BCC solid solution phases. Co, Cu and Ni elements enhance the formation of the FCC phase while Al and Cr enhance that of the BCC phase in the alloy system. BCC phases form a spinodal structure during cooling. Copper tends to segregate at the interdendrite region and forms a Cu-rich FCC phase. Low copper content renders the interdendrite as a thin film and the as-cast structure like recrystallized grain structure. The formation of BCC phases significantly increases the hardness level of the alloy system. The strengthening mechanism is discussed. 相似文献
105.
106.
Composition Range of Amorphous Mg-Ni-Y Alloys 总被引:1,自引:0,他引:1
Based on the thermodynamic point of view, a method for predication of the composition range of amorphous ter-nary alloys was proposed. The composition range of amorphous ternary alloys is determined by the comparison of the excess free energy of the amorphous alloy and the free energy of competing crystalline states. The free energy is extrapolated from the data of three binary alloys by using Toop‘s model. The method was applied to predict the composition range of amor-phous Mg-Ni-Y alloys. The theoretical results are in good agreement with the available experimental results. It indicates that the present method can be used to predict the composition range for amorphous ternary alloys. 相似文献
107.
研究了元素含量变化对8011铝合金防盗盖板综合性能的影响,在8011合金中改变Cu、Mn元素含量后可提高防盗盖板的强度,同时研究了烘烤处理后的强度变化问题。本文研究出了8011铝合金防盗盖板新的生产工艺制度。 相似文献
108.
本文在重点考虑TiNi合金高弹性变形量的前提下,采用等向强化模型,对不锈钢和超弹TiNi合金在法向接触载荷作用下的六种模型进行了有限元(FEM)分析。结果表明:在相同载荷条件下,超弹TiNi合金产生的von Mises弹性应变要高于不锈钢,但其von Mises应力和塑性应变却恰恰相反,在同一载荷下该合金发生塑性变形的区域要小于不锈钢;此外,超弹TiNi合金发生塑性变形要比不锈钢困难,所需的临界载荷值随其最大弹性变形量(屈服点处的应变值)的增加而增加。最后,基于本文的有限元计算结果对超弹TiNi合金的蘑粒磨损和疲劳磨损机制进行了讨论。 相似文献
109.
Crystalline Behavior and Magnetic Properties of Nd60Fe30-x Al10Cox(x = 0,5,10) Bulk Amorphous Alloys
Crystalline behavior and magnetic properties of Nd60Fe30-xAl10Cox( x = 0, 5, 10) bulk amorphous alloys were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and the vibrating sample magnetometer (VSM). Neither glass transition nor supercooled liquid region before crystallization was observed for the as-cast Nd60Fe30-xAl10Cox ( x = 0,5,10) bulk amorphous alloys. The glass forming ability can be improved significantly by the addition of Co. The as-cast Nd60Fe30-xAl10Cox (x = 0,5,10) alloys show hard magnetic behavior. With the addition of Co content, intrinsic coercivity (iHc) increases while the saturation magnetization(σs) and remanence (σr) decrease. The Curie temperature for the as-cast Nd60Fe30-xAl10Cox alloys increases from 451 K for x =0 to 468 K for x = 10. Some pre-cipitation of crystalline phases does not affect the hard magnetic properties of Nd60Fe30-xAl10Cox(x = 0,5,10) alloys, while the hard magnetic behavior disappears quickly after the alloys being completely crystallized. 相似文献
110.
Influence of Ni Interlayers on the Mechanical Properties of Ti6Al4V/(WC-Co) Friction Welds 总被引:2,自引:0,他引:2
M. Shamanian M. Salehi A. Saatchi T. H. North 《Materials and Manufacturing Processes》2003,18(4):581-598
Ni interlayers were introduced prior to dissimilar friction welding of Ti6Al4V base material to three cemented carbide substrates. The fracture strength of Ti6Al4V/(WC-6 wt% Co) welds were poor and were markedly improved when 20-µm thick Ni interlayers were introduced prior to dissimilar friction welding. These results were only produced when the (WC-6 wt% Co) cermet was electroplated prior to friction welding. When the Ti6Al4V alloy was electroplated prior to friction welding, fractured WC particles and cracking were observed in the (WC-Co) carbide substrate. The fracture strengths of Ti6Al4V/(WC-11 wt% Co) and Ti6Al4V/(WC-24 wt% Co) welds were not improved when 20-µm thick Ni interlayers were introduced prior to friction welding. During mechanical testing, the Ni layer retained at the dissimilar joint interface created a region of weakness. 相似文献