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研究了添加Cr、Ni、Mo合金元素的球墨铸铁,分别以90°和45°冲击角度在酸性、中性和碱性石英砂介质中的冲蚀腐蚀磨损特性。结果表明:球墨铸铁的冲蚀腐蚀磨损耐磨性随合金元素的加入而增加,并且随介质pH值和冲击角度的增加而增加。球墨铸铁冲蚀腐蚀磨损的机理,在酸性介质中是以粒子显微切削和腐蚀共同作用为主,而在中性和碱性介质中是以粒子显微切削为主,腐蚀的作用很弱。 相似文献
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高速电弧喷涂FeCrAl涂层和3Cr13涂层的冲刷腐蚀性能 总被引:1,自引:0,他引:1
采用液/固两相流冲刷腐蚀磨损实验机.研究了高速电弧喷涂FeCrAl涂层和3Cr13涂层在酸性浆料中不同试验条件下的冲蚀行为,并用扫描电镜分析了涂层冲蚀磨损后的表面形貌.结果表明:同一冲刷角度下,冲刷速度的提高加剧了涂层的损伤,FeCrAl涂层的冲蚀失重率远小于3cr13涂层,耐蚀性好的FeCrAl涂层以磨损为主,而耐蚀性差的3Cr-13涂层以腐蚀为主;同一冲刷速度下,两涂层均在冲蚀角为30°时失重率最高.低冲刷角度时,冲刷磨损机理以切削为主;高冲刷角度时,既有切削作用也有冲击作用. 相似文献
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采用三体腐蚀磨损试验方法,研究了低铬铸铁在含Cu2 、Fe3 和SO42-离子的介质中的腐蚀磨损特性,并对腐蚀磨损机理进行了分析.结果表明,随着介质中Fe3 和SO2-4离子浓度的增加,低铬铸铁的腐蚀磨损耐磨性降低,而随着Cu2 离子浓度的增加,则耐磨性表现出先降低后增加的趋势.低铬铸铁在Cu2 和SO2-4离子介质中的磨损机制以显微切削、犁沟和腐蚀剥落为主,在Fe3 离子介质中以腐蚀和显微切削、剥落为主,但在原始介质中,则以显微切削和犁沟为主,兼有少量剥落.因此,介质中的离子参与了低铬铸铁的磨损过程. 相似文献
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通过对泵用过流部件材料55#碳钢和1Cr18Ni9Ti不锈钢在不同冲蚀速度、不同浆料含砂量及不同冲蚀角度条件下的冲蚀磨损腐蚀试验,探索了材料的冲蚀失效规律及微观破坏机制.结果表明,材料的冲蚀磨损失重率随冲蚀速度、浆料含砂量的增加而增加,且1Cr18Ni9Ti的抗冲蚀性能优于55#钢;冲蚀角度对材料的冲蚀性能影响最为显著,在0°~45°时冲蚀失重率随着冲蚀角度的增大而增大,45°时出现极大值,450~600时材料冲蚀失重率随着冲蚀角度的增加而减小;腐蚀对材料冲蚀性能的影响不容忽视. 相似文献
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冲击角度对WC/铁基表面复合材料冲蚀磨损性能的影响 总被引:4,自引:2,他引:4
采用负压铸渗工艺制备了颗粒体积分数为30%左右的WC/铁基表面复合材料,研究了不同冲击角度对复合材料冲蚀磨损性能的影响.结果表明,复合材料的体积磨损率随冲击角α的增大先增大,然后减小,最后又不断增大,分别在50°和70°处出现波峰和波谷.冲蚀浆料中固体粒子对试样表面的作用可以分解为平行于试样表面的切削作用和垂直于试样表面的冲击作用,其相互协同作用影响了复合材料冲蚀磨损性能.随着冲击角的变化,切削作用和冲击作用对基体对颗粒的支撑效应和颗粒对基体的阴影效应产生了很大的影响,从而影响了复合材料的冲蚀磨损性能. 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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Z. Sun S.L. Zheng Y. Zhang 《金属学报(英文版)》2007,20(3):187-192
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process. 相似文献
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R. González-Martínez 《金属学报(英文版)》2007,20(4):235-240
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke. 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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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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This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before. 相似文献
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Chao Yang He-Fei Huang Massey de los Reyes Long Yan Xing-Tai Zhou Tian Xia De-Liang Zhang 《金属学报(英文版)》2015,28(7):809
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties. 相似文献
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Lei Li Bo Xu Wei-Ping Tong Hui Zhang Chun-Yan Ban Li-Zi He Zhi-Hao Zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui 《金属学报(英文版)》2015,28(6):725
A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed. 相似文献
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综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。 相似文献