共查询到19条相似文献,搜索用时 171 毫秒
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奥氏体不锈钢离子渗碳后的腐蚀行为 总被引:1,自引:0,他引:1
为了提高奥氏体不锈钢零件的使用寿命,利用低温离子渗碳技术对AISI 316L奥氏体不锈钢进行了表面渗碳处理.用X射线衍射仪和光学显微镜分析了渗碳层的微观组织结构,用显微硬度计测试了渗碳层的硬度分布,通过电化学极化曲线测试技术和化学腐蚀试验研究了离子渗碳AISI 316L不锈钢的腐蚀行为.渗碳层为单相碳过饱和奥氏体固溶体,由此明显提高了AISI 316L不锈钢的抗腐蚀性能,渗碳层硬度梯度平缓,表面显微硬度高达900 HV.结果表明,奥氏体不锈钢低温离子渗碳处理不仅提高了其表面硬度,而且提高了不锈钢表面的耐腐蚀性能,从而提高了其使用寿命. 相似文献
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对纯钛进行表面机械研磨处理(SMAT),并研究其组织结构以及力学性能的变化.研究结果表明,径SMAT处理后,纯钛的表面形成了纳米晶层,而整体转变成为梯度材料.与SMAT处理前的纯钛相比,处理后材料的弹性模量下降,屈服强度和抗拉强度提高而塑性下降. 相似文献
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目的 探究不同参数的脉冲电流处理(EPT)对轧制316L不锈钢拉伸性能、显微硬度及微观组织的影响。方法 将轧制的316L不锈钢作为原始样,调节流过样品的脉冲电流密度,分别为130、170、190、260、310 A/mm2,分析脉冲电流密度与其拉伸性能和显微硬度的关系。结果 轧制316L不锈钢的抗拉强度和显微硬度随着脉冲电流密度的增大呈现先增大后减小的趋势,其中当脉冲电流密度为170 A/mm2时达到峰值,抗拉强度由1 485 MPa提升到1 625 MPa,同时显微硬度也由431HV增大到473HV。通过电子背散射衍射分析微观组织可知,与原始样相比,经过脉冲电流处理的样品晶粒尺寸明显减小,马氏体含量明显增多,脉冲电流处理可以促使微观组织快速均匀化。结论 脉冲电流处理可以在短时间内实现轧制316L不锈钢组织的均匀化调控,有效改善轧制316L不锈钢的微观组织,减少轧钢形变织构,促使参与的奥氏体转变为马氏体,使微观组织趋于稳定,同时还可以使轧制316L不锈钢晶粒快速细化,达到细晶强化的效果,有效提高整体抗拉强度和显微硬度。 相似文献
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表面纳米化预处理对316L不锈钢渗氮层摩擦学性能的影响 总被引:2,自引:0,他引:2
为改善奥氏体不锈钢的表面硬度和耐磨性,采用超声滚压与离子渗氮复合工艺对316L不锈钢表面进行了表面强化处理。利用扫描电镜(SEM)、硬度计、X射线衍射仪(XRD)和能谱仪以及摩擦磨损试验机等测定了渗氮层的硬度、深度、含氮量和物相组成,研究了表面晶层组织结构对离子渗氮行为和渗氮层在润滑油条件下摩擦学性能的影响。结果表明:直接渗氮和超声滚压/渗氮试样表层组织均由S、γ'、ε和Cr N相组成,渗氮层厚度均为20μm,直接渗氮层以S相为主,超声滚压后渗氮层以ε和γ'相为主,组织结构较为致密;超声滚压/渗氮层的平均渗氮含量是直接渗氮层的2.88倍,摩擦系数降低了0.04,显微硬度和耐磨性是直接渗氮层的1.15倍和2.76倍;超声滚压处理诱使316L不锈钢表面形成的纳米晶层组织结构增强了渗氮试样表面的催渗效能和对渗氮层的支撑强度,超声滚压后渗氮试样的表面耐磨性能最好。 相似文献
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B. Arifvianto Suyitno M. Mahardika P. Dewo P.T. Iswanto U.A. Salim 《Materials Chemistry and Physics》2011
Surface roughness and wettability are among the surface properties which determine the service lifetime of materials. Mechanical treatments subjected to the surface layer of materials are often performed to obtain the desired surface properties and to enhance the mechanical strength of materials. In this paper, the surface microhardness, roughness and wettability of AISI 316L stainless steel resulting from surface mechanical attrition treatment (SMAT) are discussed. The SMAT was conducted with various processing parameters, including the duration of treatment, the number and diameter of milling ball, and the motor speed of the SMAT machine. The result indicates an increasing surface microhardness due to the SMAT. A harder surface is yielded by the SMAT with a longer duration, a bigger and a larger number of milling balls, and a higher vibration frequency. The SMAT also creates craters on the steel surfaces which correspond to the increasing roughness from 0.046 μm to the values in ranging from 0.681 to 0.909 μm. The change on the surface roughness by the SMAT does not only depend on the duration of treatment, but also the other processing parameters. In addition, the wettability of AISI 316L surface slightly increases by the SMAT as seen on the decreasing droplet contact angle from 88.6° to the values ranging from 74.4° to 87.0°. Such a droplet contact angle reduction is related to the increasing surface roughness after the SMAT. In conclusion, this study reveals the possibility of the SMAT to be used for surface properties optimization in addition to the strength enhancement of stainless steel. 相似文献
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Niobium oxide was prepared using sol–gel process and coated on 316L stainless steel (SS) substrate via dip-coating technique. The surface characterization results after a thermal treatment revealed that the coated surface was porous, uniform and well crystalline on the substrate. The corrosion resistance and bioactivity of the porous niobium oxide coated 316L SS in simulated body fluid (SBF) solution was evaluated. The in vitro test revealed a layer of carbonate-containing apatite formation over the coated porous surface. The results indicated that the porous niobium oxide coated 316L SS exhibited a high corrosion resistance and an enhanced biocompatibility in SBF solution. 相似文献
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随着20/316L双金属管在油气生产中的推广应用,关于内衬316L不锈钢的腐蚀失效问题日益突出,尤其是条件苛刻的酸性集输环境下,目前相关研究不多.利用扫描电镜(SEM)、能谱仪(EDS)等测试手段对20/316L双金属管在含H2S-Cl-的酸性集输环境中出现的腐蚀失效问题进行了系统分析,探讨了腐蚀失效的原因.结果表明:20/316L双金属管腐蚀类型为局部腐蚀,主要分布于内衬管316L的底部.腐蚀失效的主要原因是腐蚀介质中存在高浓度的H2S与Cl-,共同促进了钝化膜的破裂与点蚀的发展.当存在较高浓度的H2S与Cl-时,钝化膜薄弱处与电位较低的非金属夹杂物处易发生钝化膜的破裂与金属基体的快速溶解而成为点蚀源,形成点蚀. 相似文献
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Surface Nanocrystallization of Commercial Pure Titanium Induced by SMAT and Its Properties 总被引:1,自引:0,他引:1
Shulan ZHANG Huaining CHEN Quanhong LINInstitute of Metai Research Chinese Academy of Sciences Shenyang China 《材料科学技术学报》2004,20(6):716-718
In this paper the preparation technique of surface nanocrystallization in commercial pure titanium was carried out by surface mechanical attrition treatment (SMAT). The mean grain size was calculated by using X-ray diffraction (XRD) and transmission electron microscope (TEM), and the results showed that the mean grain size of the surface was refined to nm Ievel after SMAT treatment. Nanocrystallized surface layers were formed after treated for 5, 15, 30 and 60 min. Microhardness experimental results implied the microhardness obviously increased on the surface layer and it also showed the variation of microhardness at the cross section. Corrosion test results showed the corrosion resistance of the surfaces in the original commercial pure titanium treated by SMAT was not improved in HCI solution. The corrosion micrographs were observed by scanning electron microscope (SEM). 相似文献
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J. Baszkiewicz J.A. Kozubowski D. Krupa M. KAMIŃSki A. Barcz G. Gawlik J. Jagielski 《Journal of Materials Science》1998,33(18):4561-4568
The structure of the surface layers and the corrosion resistance of austenitic stainless steels after silicon-ion implantation, were examined. The implanted silicon doses were 1.5×1017, 3×1017 and 4.5×1017 Si+ cm-2. Implantation with all these doses gave an amorphous surface layer. When samples implanted with 1.5×1017 Si+ cm-2 were annealed at temperatures of 300 and 500 °C, their surface structure remained unchanged. After annealing at 650 °C, the amorphous layer vanished. It was determined how, in terms of corrosion resistance, the amount of implanted silicon, subsequent heat treatment and long time exposure, affect highly corrosion-resistant austenitic stainless steel (18/17/8) in comparison to the 316L austenitic stainless steel subjected to the same treatment. Corrosion examinations were carried out in 0.9% NaCl at a temperature of 37 °C. After silicon-ion implantation the corrosion resistance of the 316L steel increased while that of highly resistant (18/17/8) did not. The corrosion resistance of the investigated steels, both implanted and non-implanted, increased with the exposure time of the samples in the test environment. © 1998 Kluwer Academic Publishers 相似文献
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几种电弧喷涂金属涂层在酸性土壤模拟液中的腐蚀行为 总被引:2,自引:0,他引:2
通过自然浸泡、动电位极化、电化学阻抗谱技术研究了电弧喷涂Zn、Zn15Al和316L不锈钢三种单层涂层和底层Zn或Zn15Al表层316L两种双层复合涂层喷涂试样在鹰潭酸性土壤模拟液中的腐蚀速率和腐蚀行为,以确定适合预应力高强混凝土管桩(PHC管桩)金属端头抗华南酸性土壤腐蚀的涂层体系.结果表明:Zn、Zn15Al、Zn-316L和Zn15Al-316L涂层均能明显抑制基体Q235钢的腐蚀;Zn和Zn15Al涂层表面的腐蚀产物膜致密且与涂层牢固结合,其耐蚀性指标随腐蚀时间延长而明显变好;腐蚀中后期Zn15Al涂层的耐蚀性指标稍优于Zn涂层;316L涂层的耐蚀性随腐蚀时间延长而急剧下降. 相似文献
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M. Laleh Farzad Kargar 《Materials Letters》2011,65(12):1935-1937
The effects of surface nanocrystallization via surface mechanical attrition treatment (SMAT) on degree of sensitization (DOS) of an austenitic stainless steel were investigated by means of double loop electrochemical potentiokinetic reactivation (DLEPR) test. The treated sample with grain size about 10 nm showed very low degree of sensitization value which can be considered as the non-sensitized material. This is mainly due to the formation of twin boundaries in the microstructure of the SMATed sample which weren't susceptible to carbide precipitation because of their regular and coherent atomic structure and extreme low grain boundary energy as compared with those of other grain boundaries. 相似文献
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One of the main problems of stainless steel is its poor pitting corrosion resistance in the aggressive environment containing Cl-, such as seawater. In this paper we investigated the corrosion behavior of the 316 stainless steel coated by cerium oxide nanocoating prepared by sol-gel process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of cerium oxide nanocoatings in 3.5% NaCl solution. The microstructure of the cerium oxide was examined by scanning electron microscopy (SEM) and the formed phases was identified by X-ray diffraction (XRD). The pitting corrosion resistance of the cerium oxide nanocoating was found to be improved after heat treatment of the cerium oxide nanocoating at 300℃ for 30 min. 相似文献
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《Vacuum》2013
The role of surface mechanical attrition treatment (SMAT) on pack boronizing of AISI H11 type tool steel is addressed. SMAT induced plastic deformation, enabled nanocrystallization at the surface, reduced the grain size and increased the volume fraction of non-equilibrium gain boundaries, increased the accumulation of defects and dislocations at the grain boundaries and within the grains. These features helped to promote the diffusion of boron during boronizing and increased the case depth and hardness of the borided layer. Duplex treatment on SMATed H11 steel samples helps to achieve a higher case depth when compared to the single stage treatment. The findings of the study suggest that SMAT can be used as a pre-treatment for boronizing of H11 tool steel. 相似文献