共查询到18条相似文献,搜索用时 125 毫秒
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研究了稀土元素对齿轮钢碳氮共渗过程及其摩擦磨损性能的影响.结果表面:稀土对齿轮钢碳氮共渗过程有明显的催渗作用;稀土在碳氮共渗中渗入钢表面起微合金化作用改善了渗层组织;稀土碳氮共渗处理后的抗干磨损性能及抗滑动磨损性能均明显优于普通碳氮共渗处理. 相似文献
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为取代钢领生产厂家现行的碳氮共渗工艺,采用"无毒液体C-N-RE共渗"对20钢制纺织钢领进行了共渗试验,对共渗试样的显微组织、截面显微硬度、渗层碳浓度和稀土元素浓度进行了测定和研究。结果表明,经"无毒液体C-N-RE共渗"淬火后,20钢制纺织钢领的表面碳浓度大大增加,显微硬度大大提高,显微组织主要包含碳氮化合物、针状马氏体和残余奥氏体,稀土元素起到了良好的催渗作用。 相似文献
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本文研究了稀土元素对碳氮共渗过程中渗层浓度的影响。试验结果表明,稀土可使共渗表层碳氮浓度有所提高,渗层深度增加。用电子探针能谱测出渗层沿表面的碳浓度分布曲线,从而进一步证实了稀土的活化催渗作用。 相似文献
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测试了20Cr2Ni4A钢820C碳氮共渗层中的碳氮马氏体低温回火时的硬度变化和工业纯铁经680C氮碳共渗后渗层中的含氮马氏体回火过程中显微硬度的变化。 相似文献
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通过电化学方法测试了不同电解液中CL-璃子浓度、温度以及pH值对稀土催渗Q235钢渗层的极化曲线的影响,分析了这3种因素对稀土催渗O235钢渗氮层腐蚀性能的影响规律.结果表明,在中性、碱性溶液中,在室温下和一定Cl-离子浓度下渗氮层具有良好的耐蚀性能,从而说明了稀土催渗渗氮层比常规渗氮层具有更优越耐腐蚀能力的基本原因.此外,分别对Q235钢稀土催渗渗氮层和常规渗氮层的组织结构进行了金相观测,表明稀土催渗渗氮层生成厚约28μm的晶粒细小,组织致密的白亮层,从而具有良好的耐蚀性和更高的硬度. 相似文献
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HB5493—《航空钢制件渗碳、碳氮共渗渗层深度测定方法》已经颁布实施。HB5493是HB5023—《钢的渗碳、碳氮共渗、氮化层深度测定方法》中《钢的渗碳、碳氮共渗渗层深度测定方法》部分的修订版。内容上除保留原标准中高倍组织测定法、低倍组织测定法及断口测定法外,增加了用维氏硬度法测渗层深度,并且是推荐 相似文献
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为提高TiAl基合金的耐磨性及抗高温氧化性,利用渗氮在TiAl基合金表面形成氮化物,以提高耐磨性;渗碳形成致密且与基体结合牢固的碳化物层,提高抗高温、抗氧化性;将二者结合,采用辉光离子碳氮共渗的方法,研究了渗层的相结构组成、不同工艺参数对TiAl基合金离子碳氮共渗后渗层厚度以及表面硬度和耐磨性的影响.结果表明:TiAl基合金共渗层是由碳氮化合物层与过渡层组成的复合相结构;随共渗温度的升高和时间的延长,渗层厚度增加;与未经共渗处理的试样相比,表面硬度及耐磨性显著提高.X射线衍射结果显示,渗层主要由TiC,TiN,AlTi3,Al2O3等组成. 相似文献
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Sb合金化对AE41镁合金耐热性能的影响 总被引:15,自引:0,他引:15
采用X射线、光学显微镜、电子探针、扫描电镜等手段研究了Sb合金化对AE41(Mg-4Al-1RE)镁合金组织和耐热性能的影响.结果表明,Sb取代Al优先与RE形成以RE2Sb相为主的高熔点弥散颗粒质点,而枝条状Al11RE3相数量和尺寸减小.Al11RE3相对基体的割裂作用的减弱,RE~Sb质点的弥散强化作用、以及Sb、RE等元素的固溶强化作用,使合金的常温和高温力学性能尤其是塑韧性显著提高,并且有效地改善了高温抗蠕变能力.过量的Sb反而降低了合金的力学性能和耐热性能.合金的断裂为具有塑性特征的准解理断裂. 相似文献
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Lalgudi Venkataraman Ramanathan Marina F. Pillis Stela Maria C. Fernandes 《Journal of Materials Science》2008,43(2):530-535
Rare earths (RE) have been used to increase high temperature oxidation resistance of chromia and alumina forming alloys. The
RE can be added as elements (or oxides) to the alloys or applied as oxide coatings to the alloy surface. This paper presents
the effect of different RE oxide coatings and lanthanum chromite coatings on the high temperature oxidation behavior of Fe20Cr
and Fe20Cr4Al alloys. The oxidation resistance of the Fe20Cr alloy increased with increase in ionic radius of the RE element
in the coating. The RE oxides decreased chromia growth rate more than alumina growth rate. In extended cyclic oxidation tests
that were carried out from peak temperatures of 900 °C, 1,000 °C and 1,100 °C to room temperature at cooling rates of 300 °C/s
and 1,000 °C/s, the La2O3 coating increased cyclic oxidation resistance of the Fe20Cr alloy significantly more than the Pr2O3 coating. The role of RE in increasing overall oxidation resistance of chromia forming alloys is discussed. 相似文献
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This paper studied the phenomenon of room creep deformation and its effect on tensile property of a X70 pipeline steel under stress-control loading pattern using round tensile test specimen. Significant time-dependent deformation under constant load was observed in the steel at room temperature, and the deformation is not only dependent on loading stress rate but also dependent on the loading process. It is also found that the loading-unloading-reloading process reduces the subsequent creep strain, while the occurrence of room temperature creep obviously enhances the subsequent yielding strength and the flow stresses. 相似文献
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B. I. Koval'chuk L. V. Zaitseva A. A. Lebedev V. V. Kosarchuk 《Strength of Materials》1991,23(10):1101-1105
Results are given for a study of the kinetics of phase transformations in chromium-nickel austenitic steel with repeated plastic deformation including under conditions when prior and repeated loading differ in temperature and form of stressed state. It is established that prior low-temperature deformation intensifies the process of martensite formation at room temperature whereas deformation under room temperature conditions has almost no effect on martensitic transformation kinetics at low temperature.Translated from Problemy Prochnosti, No. 10, pp. 46–50, October, 1991. 相似文献
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Cai Weiping 《Journal of Materials Science》1991,26(14):3813-3816
The dislocation internal friction at room temperature for 99.99% pure Al with different rare-earth (RE) contents (0–3 wt %) was measured with Ke's torsion pendulum in a vacuum. A new method is presented for accurately determining the parameters of Granato-Lück plot and processing the experiment data. It was found that at room temperature the unpinning stress of dislocations and the slope of the G-L plot increase with RE content and tend to change little when RE ? 0.1 %. The binding energy between RE atom and dislocation, and the lattice solubility of RE in Al at room temperature were obtained according to the dependence of unpinning strain on temperature, which are about 0.19 eV and 0.0003 wt%, respectively. The existence of solid solution RE in dislocations and the lattice was confirmed and some behaviour of RE in the interior of the Al grain mentioned in part I was also proved. 相似文献