共查询到20条相似文献,搜索用时 250 毫秒
1.
《中国有色金属学报》2016,(5)
采用真空气压浸渗法制备纤维体积分数为51%的三维五向编织M40碳纤维增强铝基复合材料(3D-C_f/Al),研究纤维预热温度对3D-C_f/Al复合材料显微组织与力学性能的影响,并对比研究3D-C_f/Al复合材料与单向连续C_f/Al复合材料的差异。结果表明:复合材料致密度随着编织体预热温度的提高而增大,提高预热温度可有效减少复合材料内部孔洞和纤维偏聚等浸渗缺陷;复合材料的拉伸强度随纤维预制体预热温度的提高而显著降低。其中,在预热温度500℃、浸渗温度720℃、浸渗压力7 MPa和保压时间20 min的工艺条件下,所制备的3D-C_f/Al复合材料致密度为97.3%,拉伸强度为777.8 MPa,弹性模量为186.1 GPa。 相似文献
2.
低浸渗压力制备纤维增强铝基复合材料 总被引:2,自引:0,他引:2
利用液态浸渗技术制备了氧化铝纤维增强铝基复合材料。研究结果表明,在低压下使液态合金浸渗纤维预制件制备铝基复合材料是可行的。在浸渗过程中,液态合金的温度对浸渗压力有较大影响。所制备的复合材料具有均匀的显微组织,基体中的共晶组织可依附在纤维表面形核生长。 相似文献
3.
选用先驱体法制备的直径10~15μm束丝SiC纤维作为增强体材料,采用真空气压浸渗法制备了SiCf体积分数为40%的连续SiCf/Al复合材料,研究纤维预热温度对复合材料显微组织与力学性能的影响。结果表明:复合材料中原局部存在少量团聚的SiC纤维束随着纤维预热温度的提高,纤维团聚减少,分布更趋于均匀;而复合材料致密度和抗拉强度随纤维预热温度的升高先逐渐增加后缓慢降低;其中,在纤维预热温度为500℃、浸渗温度为730℃、浸渗压力为7 MPa和保压时间为5 min的浸渗工艺条件下所制备的连续SiCf/Al复合材料的致密度为97.24%,抗拉强度达到768.9 MPa。 相似文献
4.
5.
石墨颗粒铝基复合材料的研制 总被引:5,自引:1,他引:4
用预成形压力浸渗技术制备了石墨颗粒铝基复合材料,研究了石墨颗粒预成形的制备及压力浸渗时铝液温度、保温时间和石墨颗粒尺寸对复合材料制备的影响,测定了石墨颗粒铝基复合材料磨损特性。 相似文献
6.
《特种铸造及有色合金》2015,(7)
三维编织碳纤维增强铝基复合材料(3D-Cf/Al复合材料)具有耐冲击、不分层、抗开裂、耐疲劳、整体性强等优点,但浸渗过程中存在难以浸渗和过度界面反应等问题。在采用真空气压浸渗制备单向排布Cf/Al复合材料的工艺试验基础上,进行了三维五向编织Cf/Al复合材料的真空气压浸渗工艺研究,得到了3D-Cf/Al复合材料真空气压浸渗成形工艺参数。在预热温度为500~550℃、浸渗温度为730℃、保压时间为20min时,制备出的3D-Cf/Al复合材料浸渗良好,其致密度达到95.88%,抗拉强度达到782.33 MPa。 相似文献
7.
8.
利用自行设计的试验装置采用气压浸渗法成功制备出Al2O3短纤维增强铝基复合材料,对金相组织和硬度进行了分析,得出了温度、体积分数、压力对浸渗的影响结果.证明了气压制备短纤维铝基复合材料的可行性. 相似文献
9.
10.
压铸工艺生产的铝基复合材料的组织和性能 总被引:2,自引:1,他引:1
报道了压铸浸渗法生产的γ Al2 O3 长纤维、δ Al2 O3 短纤维和SiC颗粒强化铝基复合材料的组织特征和强度性能检测结果。试验结果表明 ,采用优化工艺条件 ,在工业压铸机上可以生产出高浸渗质量、可热处理的铝基复合材料。所获复合材料与 13 0MPa挤压浸渗生产的复合材料相仿 ,具有理想的工艺质量和组织结构 ,强度性能达到或超过混合律的预测值。 相似文献
11.
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
12.
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
13.
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
14.
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
15.
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
16.
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
17.
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
18.
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
19.
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
20.
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