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The in situ synthesized NbC particles reinforced Ni-based alloy composite coating was produced by laser cladding a precursor mixture of Ni-based alloy powder,graphite and niobium powders on a steel substrate.The microstructure,phase composition and wear property of the composite coating were investigated by means of scanning electron microscopy(SEM),X-ray diffraction(XRD)and dry sliding wear test.The experiment results show that the composite coating is homogeneous and free from cracks,and about 0.8 mm thick.The microstructure of the composite coating is mainly composed of NbC particles,CrB type chromium borides,γ-Ni primary dendrites,and interdendritic eutectics.CrB phases often nucleate and grow on the surface of NbC particles or in their close vicinity.NbC particles are formed via in situ reaction between niobium and graphite in the molten pool during the laser cladding process and they are commonly precipitated in three kinds of morphologies,such as quadrangle,cluster,and flower-like shape.Compared with the pure Ni-based alloy coating,the microhardness of the composite coating is increased about 38%,giving a high average hardness of HV0.21000,and the wear rate of the composite coating is decreased by about 32%,respectively.These are attributed to the presence of in situ synthesized NbC particles and their well distribution in the coating. 相似文献
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MA Fe-(Nb,Ti)-B纳米晶粉末热压烧结及磁性能 总被引:1,自引:0,他引:1
研究了MA法和热压烧结工艺制备的Fe84Nb7B9和Fe80Ti8B12合金粉末的产物及其块体合金的微观组织结构和磁性能。结果表明:(1)20hMA后,Fe84Nb7B9和Fe80Ti8B12均形成了单相bcc米晶过饱和固溶体,相对前者,后者纳米晶组织热稳定性明显提高,过饱和固溶体相分解温度略有降低;(2)在30MPa/900℃/0.5h热压条件下,Fe84Nb7B9和Fe80T8B12块体合金相对密度分别为96.7%和95.5%,相对前者(多相组织),后者由超细晶(50~200mm单相α-e组成;(3)Fe80TiB12块体合金软磁性能(σ8=198.6emu/g,Hc=54.6Oe)明显高于Fe84Nb7B9块体合金(σ8=162.9emu/g,Hc=105.1Oe),此与纳米晶粉末在热压烧结过程中所形成相的种类和晶粒尺寸大小有关。 相似文献
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锌铝基Al2O3陶瓷复合层上激光重熔区的相组成及成因 总被引:2,自引:0,他引:2
本文采用带能谱扫描电子显微镜、X衍射等方法 ,分析了锌铝合金基陶瓷复合层激光重熔后相的结构和成分 ,并对其形成原因进行了探讨。 相似文献
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随着我国电力产业迅猛发晨,对变压器的需求极其巨大.初步估计整个验配电系统的市场容量将达到近400亿人民币。同时.我国变压器的总损耗占系统发电量的10%左右.降低变压器损耗势在必行.这对我国采用高性能纳米晶较磁合金来替代变压器中的硅钢片提供了巨大的市场. 相似文献
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新型钴基高温合金的组织结构与力学性能 总被引:3,自引:0,他引:3
对新设计的三种新型钴基高温合金的组织结构及性能进行了研究.结果表明:钨作为合金的主要固溶元素,其含量必须控制在17.0%~18.5%的范围内,才能有效地起到固溶强化作用.过多的钨元素将形成大量的析出相,晶粒也因此而细化,虽然合金的室温强度会有所提高,但是在1200℃高温下,变得较为薄弱的大量晶界却使强度明显降低. 相似文献
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Ni-Ti形状记忆合金(SMA)薄膜由于其尺寸小输出功大,是一种具有诱人前景的微机械材料.主要介绍了Ni-Ti薄膜的马氏体相变及时效稳定性、力学性能.并介绍了其最新的应用研究. 相似文献
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