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1.
董守安  杨晓云 《贵金属》1996,17(4):32-36
在含有CuSO4的HCl溶液中,利用电生的CuCl2^-对Ru(Ⅳ)做库仑滴定。获得毫克量钌转化成单一RuCl6^2-的最佳途径,结果具有较高的准确度和精度。同时还研究了钌的存在价态和状态。  相似文献   

2.
Cu-Al爆炸焊结合层的透射电镜研究SCIEI   总被引:6,自引:0,他引:6  
周邦新  蒋有荣 《金属学报》1994,30(3):B104-B108
用透射电镜(TEM)研究了Cu-Al爆炸焊的结合层,爆炸焊连接是由熔化和扩散共同作用的结果.在熔区内存在非晶态与晶态,晶态主要由CuAl_2.Cu_3Al_2和Cu_4Al组成.与熔区相邻的Al侧发生了再结晶,Cu向Al中的扩散距离<100nm,析出针状的CuAl_2相与熔区相邻的Cu侧只发生了回复,Al向Cu中的扩散距离<100nm,形成了新相层,可能是Cu_3Al_2和Cu_4Al.在非熔化区存在Cu和Al的互扩散,形成新相层的厚度<100nm.  相似文献   

3.
目前实用的形状记忆合金有NiTi、Cu-Zn-Al和Cu-Al-Ni合金,其应用温度范围都在室温至200℃以下,都不能在较高的温度下使用。本文作者开发了新一类高温形状记忆合金,它们是近于等原子成分的钽-钌合金和铌-钌合金,这类合金具有高于1000℃的形状记忆转变温度,是当前的最高温形状记忆合金。本文研究了这两个合金(Ta50Ru50和Nb50Ru50)的形状记忆效应。研究用的合金试样,是采用高纯度元素原料在氩气氛下用电弧熔炼法制备的,两个合金均采取反复重熔以确保其成分的均匀性。TaRu合金经过1…  相似文献   

4.
Cu-Al爆炸焊结合层的透射电镜研究   总被引:1,自引:0,他引:1  
周邦新  蒋有荣 《金属学报》1994,30(15):104-108
用透射电镜(TEM)研究了Cu-Al爆炸焊的结合层,爆炸焊连接是由熔化和扩散共同作用的结果.在熔区内存在非晶态与晶态,晶态主要由CuAl_2.Cu_3Al_2和Cu_4Al组成.与熔区相邻的Al侧发生了再结晶,Cu向Al中的扩散距离<100nm,析出针状的CuAl_2相与熔区相邻的Cu侧只发生了回复,Al向Cu中的扩散距离<100nm,形成了新相层,可能是Cu_3Al_2和Cu_4Al.在非熔化区存在Cu和Al的互扩散,形成新相层的厚度<100nm.  相似文献   

5.
EuCl3—CaCl2二元系相图   总被引:4,自引:1,他引:4  
用差热分析法研究了EuCl3CaCl2二元体系相图,发现该体系有一个异份熔化化合物EuCl3·3CaCl2。体系转熔点为570℃,EuCl3摩尔分数45.4%;低共熔点为522℃,EuCl3摩尔分数66.8%。  相似文献   

6.
Cu2O-Al体系的化学反应机理   总被引:5,自引:0,他引:5  
在对 Cu2O-Al体系进行热力学分析的基础上.测试了 Cu2O与Al粉末压块在不同介质温度下反应的热分析曲线。并对反应后的试佯进行了X射线衍射分析.结果表明、Cu2O—Al体系反应随介质温度升高可分为 3个不同阶段:第1阶段、体系温度 T<910 K,有少量 Al2O3和 Cu生成:第 2阶段.体系温度为 910 K≤ T<1103 K,Cu2O—Al体系未发生化学反应:第 3阶段.体系温度为 1103 K≤ T≤1373 K,Cu2O—Al体系发生化学反应.其产物为 Cu,Al2O3及 CuAlO2.  相似文献   

7.
储双杰  吴人洁 《铸造》1998,(10):4-7
本文研究了凝固冷却速度对挤压铸造莫来石短纤维增强Al45Cu复合材料的凝固组织和显微偏析的影响。结果表明:αAl相在短纤维间隙中形核并向纤维表面生长,θCuAl2相以莫来石短纤维为基底非均质形核;随凝固冷却速度的减慢,θCuAl2相析出量增多且由蠕虫状向块状转变,纤维表面的Cu浓度增大,纤维间隙中Cu浓度减小,即Cu元素的显微偏析增大,复合材料的抗弯强度降低。  相似文献   

8.
Cu基形状记忆合金的时效   总被引:5,自引:2,他引:5  
对比研究了时效对亚共析Cu-12.0Al-5.0Ni-2.0Mn-1.0Ti(wt.-%)合金与Cu-20.0Zn-6.0Al-微量B(wt.-%)合金热稳定性的影响。结果表明,无论在母相状态或马氏体相状态,Cu-Al-Ni合金的时效热稳定性均远优于Cu-Zn-Al合金。Cu-Al-Ni合金母相状态时效伴随着DO_3有序畴长大,基体中Al、Ni、Mn等元素贫化,导致M_s点升高,马氏体转变量降低。Cu-Zn-Al合金母相状态时效伴随贝氏体转变,引起基体富Zn富Al,导致M_s点下降,马氏体量降低。Cu-Al-Ni合金高的时效热稳定性可能来源于Ni对Al、Cu等原子扩散的阻碍作用。  相似文献   

9.
反应生成Al2O3(p)/Al—Cu复合材料的研究   总被引:11,自引:3,他引:11  
通过对CuO/Al体系反应过程的研究,采用反应生成方法制备了Al2O3(p)/Al-Cu复合材料,并对Al2O3颗粒在Al2O3(p)/Al-Cu复合材料中的分散过程做了分析,得出了制备这种复合材料的工艺条件。  相似文献   

10.
孙笠  宋启洪  胡壮麒 《金属学报》1995,31(20):341-345
本文利用机械球磨的方法将工业上广泛应用的传统的RaneyCu催化剂的前体Cu30Al70合金制成了纳米晶合金催化材料,并研究了它在木糖加氢反应中的催化活性.结果表明,制成的纳米晶合金CuAl2相的平均晶粒尺寸为12nm,球料比和球磨时间极大地影响形成的纳米晶Cu30Al70合金的晶粒尺寸,纳米晶Cu30Al70合金组织较均匀,元素分布均匀,活化后的催化剂具有较高的催化活性.  相似文献   

11.
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 (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.
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.
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.
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.
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.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
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   

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