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采用扫描电镜、透射电镜和X-射线衍射仪等方法研究了铸造ZG1Cr11Ni2WMoV马氏体耐热钢经1050℃×1 h空冷正火后在不同温度回火的显微组织及第二相析出行为。结果表明:铸造ZG1Cr11Ni2WMoV马氏体耐热钢经不同温度回火后,显微组织由板条状回火马氏体和少量δ-铁素体组成,在较低温度(550℃)回火时,高密度纳米尺寸M_6C型碳化物均匀分布在马氏体板条内,随回火温度的升高,M_6C型碳化物长大成细长针状,同时在原奥氏体晶界、马氏体板条界及δ-铁素体周围析出M_(23)C_6型碳化物,继续升高回火温度至700℃,板条内不再有M_6C型碳化物析出,板条界上M_(23)C_6型碳化物颗粒逐渐长大。 相似文献
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研究了高铬马氏体耐热钢(0.09C-10.2Cr-0.52Ni-1.52Mo-0.22V-0.07Nb-3.0Co-0.01Ti-0.0129N-0.0033B)的显微组织和力学性能.结果表明该钢经1100℃×1h空冷正火处理 750℃×1h空冷回火处理后的显微组织为板条状马氏体,在原奥氏体晶界和板条间分布有M23C6碳化物,并有少量1~3μm的M3B2颗粒,马氏体板条内部有10~30 nm的MX型析出相.短期蠕变试验数据显示其在650℃的蠕变性能优于P92钢. 相似文献
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P92钢的微观组织和硬度 总被引:1,自引:0,他引:1
利用布氏硬度计、光学显微镜、扫描电子显微镜和X射线衍射仪研究了不同回火温度下P92钢的微观组织和硬度变化。结果表明,P92钢正火组织主要由马氏体、残留奥氏体和M23C6析出相组成,回火后温度升高到600℃时残留奥氏体才全部完成分解。低于400℃回火时因马氏体板条结构和位错组态没有明显变化,并且M23C6析出量也较少,硬度基本保持稳定;500℃回火时因亚晶强化和细小M23C6沉淀强化,硬度有所提高;继续升高回火温度,因马氏体发生高温回复,位错密度降低,M23C6也逐渐发生熟化,强化效果减弱,导致P92钢硬度逐渐降低。 相似文献
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通过冲击性能试验、硬度测试、扫描电镜和透射电镜观察等方法对630℃不同时效时间后的FB2转子钢样品进行组织观察和力学性能分析。结果表明,FB2转子钢在630℃时效过程中能够保持较好的高温稳定性; FB2转子钢的冲击断口表现为准解理脆性断裂;在时效前期,位错回复,冲击韧性提高;在时效中后期,由于析出相M23C6和Laves相在晶界位置聚集粗化,引起应力集中,冲击性能下降,时效5000 h后转子钢的冲击吸收能量为17 J;在长时时效过程中,FB2转子钢的强度下降趋势与析出相M23C6的尺寸变化趋势相一致,当析出相M23C6进入尺寸稳定期后FB2转子钢的硬度也基本稳定为253. 4 HBW(5/750),析出相M23C6是维持FB2转子钢服役性能的重要影响因素。 相似文献
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热处理工艺对403Nb钢组织与蠕变性能的影响 总被引:2,自引:1,他引:1
为扩大403Nb耐热钢的使用范围,比较研究了热连轧及热处理态403Nb钢的组织及蠕变性能。结果表明:403Nb钢在高温轧制时发生了动态回复及动态再结晶,组成相包括:α-Fe、Cr23C6及少量的NbC。其中,碳化物颗粒粗大,分布不均。经1050℃淬火后,获得了板条马氏体及残留的NbC。随着淬火温度的提高,晶粒有所长大,当温度达到1150℃时,出现较多沿晶界分布的δ铁素体。采用优化的热处理工艺,即1100℃淬火、650℃回火时,在原马氏体板条内及板条间弥散析出大量纳米级以Cr23C6为主的碳化物,此时,钢的使用温度及蠕变寿命可大幅度提高。文中阐述了钢组织的形成机制。 相似文献
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通过对在役不同外径蠕变应变状态T91管取样,采用光镜、扫描电镜及力学性能试验分析T91管在长期服役中的不同外径蠕变应变状态下组织、力学性能演变规律,研究外径蠕变应变对其组织及室温力学性能影响。结果表明,随着外径蠕变应变的增加,马氏体板条特征逐渐消失,M23C6型碳化物粗化及沿晶界析出、聚集与粗化,原奥氏体晶界和亚晶界逐渐清晰、粗化;室温屈服强度、抗拉强度随外径蠕变应变增加而降低,而断后伸长率随外径蠕变应变的增加遵循先增后降的趋势。沉淀相M23C6型碳化物粗化及所导致的板条亚结构退化、碳化物沿原奥氏体晶界和亚晶界析出及所导致的晶界变宽是T91管高温运行中外径蠕变造成强度降低和最终失效的主要原因。 相似文献
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Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
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After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献
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目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。 相似文献
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The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
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Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems. 相似文献
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The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel. 相似文献
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Tang Dynasty 《中国铸造》2014,(4):I0002-I0003
<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also 相似文献
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《中国铸造》2014,(5):464-466
The 9th China International Diecasting Congress & Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition. 相似文献
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《机床与液压》2014,(12)
正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc- 相似文献
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