纳米晶FeCuNbSiB合金中晶间非晶相的居里温度研究

按具有最佳磁性时纳米晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金的晶间非晶相的化学成分制得３种非晶条带,测量其居里温度。结果表明,在纳米晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金中,处于高居里温度α－Ｆｅ之间的纳米尺寸的晶间非晶相的居里温度高于相同化学成分的非晶合金的居里温度,这可能是由于在纳米晶合金中晶间非晶相受到α相的强的铁磁交换作用引起的。     

Fe_(76.5-x)Cu_1Nb_xSi_(13.5)B_9的磁致伸缩

Ｆｅ７６．５－ｘＣｕ１ＮｂｘＳｉ１３．５Ｂ９的磁致伸缩样品为Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１６．５Ｂ６和Ｆｅ７６．５－ｘＣｕ１ＮｂｘＳｉ１３．５Ｂ９（ｘ＝２，３和５）。Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１６．５Ｂ６非晶带经５３０℃退火，其他成分样品的退火温度...     

Fe73.5Cu1Nb3Si13.5B9非晶合金电脉冲处理与等温退火的比较

用直流高密度电脉总和可比等温退火处理Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金,并用ＸＲＤ,ＴＥＭ和穆斯堡尔谱方法进行了结构检测。结果表明,在电脉冲作用下,Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｐ９非晶合金在平均温度为４２０℃的条件下发生了纳米晶化,晶化度试样中无Ｆｅ－Ｂ相析出,无ＤＯ３型有序结构;晶化总量达３０．９％的无序ａ－Ｆｅ（Ｓｉ）相的平均尺寸为８～９ｎｍ,按二项式分布计算ａ－Ｆｅ（Ｓ     

超微晶合金的霍普金森效应研究

用霍普金森效应及Ｘ射线研究了铁基超微晶合金Ｆｅ７３．５Ｃｕ１Ｎｂ８Ｓｉ１８．５Ｂ９的居里温度和晶化过程。合金在５００℃退火１ｈ开始出现晶化相。随着退火温度的升高，晶化相的居里点由５００℃上升到５７０℃。同时，剩余非晶基体的居里点也发生变化。     

非晶态与纳米晶材料的穆斯堡尔谱及高温电阻率的研究

研究了非晶Ｆｅ７８Ｃｒ４Ｓｉ５Ｂ１３及非晶、纳米晶Ｆｅ７３５Ｃｕ１Ｎｂ３Ｓｉ１３５Ｂ９的室温穆斯堡尔谱及高温电阻率和结构驰豫。实验结果表明,两种合金的电性有大的差别,且结构驰豫对非晶、纳米晶Ｆｅ７３５Ｃｕ１Ｎｂ３Ｓｉ１３５Ｂ９的性质有大的影响。     

退火对Fe_(66)Cr_8Cu_1Nb_3Si_(13)B_9条带磁弹性的影响

退火对Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９条带磁弹性的影响测定了Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９合金带退火后纳米晶引起的变化来观察磁场与合金杨氏模量的关系。将３ｍｍ宽、２５μｍ厚的Ｆｅ６６Ｃｒ８Ｃｕ１Ｎｂ３Ｓｉ１３Ｂ９非晶合金带材切成５ｃｍ长...     

铁基软磁纳米微晶中非晶相的穆斯堡尔研究

以穆斯保尔谱分析为主要手段研究了纳米晶（ＦｅａＳｉ）０．９５Ｎｂ０．０５和Ｆｅ６９．５（ＣｕＣｒＶ）９．５Ｓｉ１３Ｂ８、Ｆｅ７３．５Ｃｕ１Ｎｂ８Ｓｉ１３．５Ｂ９合金的非晶相的微结构，介绍了实验方法，并对实验结果进行了探讨。     

超微晶合金Fe73.5Cu1Nb3Si13.5B9晶化过程的X射线研究

用Ｘ射线衍射方法研究了超微晶合金Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９在退火过程中晶化相及晶格常数的变化。经４８０℃×１ｈ退火后，合金中出现ｂｃｃＦｅ（Ｓｉ）相，６００℃出现Ｆｅ３Ｂ相，６７０℃出现Ｆｅ２３Ｂ６相。退火温度升高时，Ｆｅ（Ｓｉ）相的晶格常数由０．２８３８ｎｍ上升到０．２８４９ｎｍ合金经过５５０℃×４ｈ退火后仍只有Ｆｅ（Ｓｉ）一个晶化相，其晶格常数随时间的变化不明显。     

超微晶合金Fe73.5Cu1Nb3Si13.5B9晶化相的电镜观察及能谱分析

用透射电镜和能谱仪分析了Ｆｅ７３．５Ｃｕ１Ｎｂ３．Ｓｉ１３．５Ｂ９合金经不同温度退火后的组织，晶化相结构以及不同晶化相中的各元素含量变化，合金于４５０℃退火１ｈ析出尺寸小于５ｎｍ的ｂｃｃＦｅ（Ｓｉ）相，并且其尺寸随退火温度的升高而增大到约１５ｍｉｎ，于６００℃退火时合金中析了四方结构的Ｆｅ３Ｂ相，其晶格常数为ａ＝０．８７８ｎｍ，ｃ＝０．４３９ｎｍ在７００℃退火时出现面心立结构的Ｆｅ２３Ｂ６相，其晶     

铁基软磁纳米微晶中非晶相的穆斯堡尔研究

以穆斯堡尔谱分析为主要手段研究了纳米晶（Ｆｅ３Ｓｉ）０．９５Ｎｂ０．０５和Ｆｅ６９．５（ＣｕＣｒＶ）９．５Ｓｉ１８Ｂ８、Ｆｅ７８．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金的非晶相的微结构，介绍了实验方法，并对实验结果进行了探讨。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

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.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

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.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

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.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

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.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

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.