排序方式: 共有235条查询结果,搜索用时 16 毫秒
51.
研究了锌铝基Al2O3陶瓷层激光重熔区内陶瓷相的转变。采用METCO 4MP等离子喷涂机对基体材料表面喷涂氧化铝(Al2O3的质量分数为99%)陶瓷层。采用上海光学精密机械研究所HJ-4工业用横流CO2激光器进行激光重熔。通过X射线衍射分析和透射电镜对Al2O3陶瓷的微观结构、成分和分布的研究,得到以下结论:在等离子喷涂过程中,喷涂层中陶瓷相发生。α-Al2O3→γ-Al2O3 α-Al2O3的转变。激光重熔后,试样表层的原α-Al2O3陶瓷相、γ-Al2O3陶瓷相均转变为δ-Al2O3陶瓷相,为体心四方结构.熔池区陶瓷相主要分布在表层,次表层和过渡区。 相似文献
52.
采用金相显微镜、透射电镜、X射线衍射仪、显微硬度计以及微动磨损机研究了激光重熔等离子喷涂锌铝基Al2O3复合陶瓷涂层的组织结构、硬度及其耐磨性能.研究结果表明:等离子喷涂层由α-Al2O3和γ-Al2O3组成,层间为机械结合界面;经激光重熔后的组织为单一的体心四方结构的δ-Al2O3相,其点阵常数a0=7.943×10-8cm,c0=23.500×10-8cm,Al2O3与基体间的界面结合状况得到明显改善;熔覆后的Al2O3涂层硬度达150~170 HV100g,耐磨性能(S=L 988)比基体材料(S=2.837)有较大提高,其磨损机制是疲劳磨损和磨粒磨损,但以磨粒磨损为主. 相似文献
53.
54.
55.
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
56.
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
57.
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
58.
59.
随着世界范围内对高性能软磁材料的需求日益增加,添加不同合金元素的FINEMET合金的性能及其纳米结构的研究近年来引起了广大科研工作者的兴趣.本文回顾了不同合金元素对软磁合金材料的纳米结构和性能的影响的研究进展,并讨论了不同热处理工艺对合金软磁性能的影响.要更进一步的降低成本和提高材料性能,我们必须对合金成分,合金制备方法及热处理工艺进行优化. 相似文献
60.
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