Effect of Al on the Structure and Magnetic Properties of Nanocrystalline FeSiBPCu Melt-Spun Ribbons

In this work, we have studied the effects of the addition of Al on the structure, thermal behavior and magnetic properties of rapidly solidified Fe_83.3(Si_0.25B_0.562P_0.188)_16?xCu_0.7Al_x (x = 0, 0.5, 1 and 1.5) melt spun ribbons prepared by single roller melt-spinning process. All of the samples were studied using various techniques such as X-ray diffraction (XRD), differential scanning calorimetry, vibrating sample magnetometer and B-H loop tracer. The average crystallite sizes obtained for the Al-added samples were in the range of 10–18 nm confirmed by XRD results. Thermal analysis results revealed that by adding Al up to 1 at.%, the first crystallization peak shifted towards lower temperature and second peak to the higher temperature compared to the sample without Al. The highest maximum saturation magnetization (1.8 T) was obtained for the 0.5 at.% Al added alloy. Also the magnitude of coercivity was lowest for 1 at.% Al-added alloy. This was mainly related to the decrease of magnetostriction and magnetocrystalline anisotropy substitution of Al atoms for Si, P and Fe in the structure of bcc-Fe.     

Influence of Pr on Magnetic Properties and Microstructure of Melt-Spun （ Nd1-x Prx ） 10.5 （FeCoZr） 83.5 B6 Alloy

Inrareearthsores ,praseodymiumoftencoexistswithneodymiumandtheabundanceofPrisaboutonethirdofNd .Becauseofextremeexcellentpermanentmagneticpropertiesoftherareearth transitionmetalin termetalliccompoundNd2 Fe14 B ,Ndhasbeenwidelyutilizedsincethe 1980s .Withtheexploitationofrareearthsores ,Prisexcessiveinmarketandcheapinpricebecauseofitsnarrowapplication .ItisfoundthatPr2 Fe14 BhasasimilarmagneticpropertieswithNd2 Fe14 B[1] andcancertainlybeusedaspermanentmagneticmateri al[2～ 4 ] .Therefor…     

Cu含量对Al-Cu合金板材组织及性能的影响

本文通过先熔炼铸锭,后轧制成板材的方法,制备了不同Cu含量的铝铜合金板材,研究了Cu含量变化(1.287%～9.806%)对合金板材显微组织、力学性能和成形性能的影响。结果表明,随着Cu含量的增加,合金中弥散析出的第二相质点逐渐增多;Cu含量在5.654%～9.806%范围时合金的力学性能较为理想,当Cu含量为5.654%时,合金的成形性能最好,此时板材的极限拉伸系数为0.75,制耳率低至3.8%。     

Ni含量对Cu-Ni-Cr合金组织和性能的影响

采用中频熔炼-铁模铸造-热轧-固溶-冷轧-时效处理工艺,制备了Cu-Ni-Cr合金板材.通过拉伸力学性能测试、电导率测试、金相和透射电子显微镜观察.研究了不同Ni含量对该合金组织和性能的影响.结果表明:Cu-Ni-Cr合金在Ni含量不大于2%时.其常温力学性能相差不大,在Ni含量达到5%后强度才有较大的下降;Ni可有效地调节合金的电导率,在Ni含量从0.5%变化到5%时,合金的电导率也从64%IACS变化到20.9%IACS,因此可根据具体要求选择设计合金的成分;在此处理态下,两成分的合金Cu-1.5Ni-0.5Cr和Cu-2.0Ni-0.5Cr的高温力学性能都较好,抗拉强度在350℃时在280MPa左右,延伸率也在8%左右.     

铸造超低碳镍基合金的含铬量对其组织与性能的影响

设计了耐盐酸复合介质的新型铸造超低碳镍基合金的化学成分，着重研究了含铬量对其组织与腐蚀行为的影响。试验结果表明，含有15％Cr的超低碳铸造Ni-Cr-Mo-Fe合金，在苛刻的盐酸复合介质中具有优良的耐蚀性能，并具有良好的机械性能、切削加工性能与铸造性能。     

Effect of High-Pressure Torsion Deformation and Subsequent Annealing on Structure and Magnetic Properties of Overquenched Melt-Spun Nd9Fe85B6 Alloy

The influence of a high-pressure torsion deformation (HPTD) and subsequent annealing on the magnetic properties and phase transformations in the melt-spun Nd₉Fe₈₅B₆ alloy has been investigated. Because of the low density of nucleation centers and formation of the metastable NdFe₇ and Nd₂Fe₂₃B₃ phases, the crystallization of the nearly amorphous ribbons leads to the non-uniform and coarse Nd₂Fe₁₄B grains resulting in the lower values of the coercivity H_c and remanence B_r. The HPTD prior to annealing creates numerous α-Fe nanograins, which apparently serve as nucleation sites for Nd₂Fe₁₄B. In the ribbons subjected HPTD and annealed at 600 °C, the α-Fe and Nd₂Fe₁₄B grains are uniform and fine (13 and 22 nm, respectively) leading to the increase of H_c by 23% and the increase of B_r by 16%. Thus, HPTD is a powerful tool for improvement of the magnetic hysteresis properties in the overquenched Nd₉Fe₈₅B₆.     

纳米晶Fe-Si合金粉末的微结构及磁性能研究

通过高能球磨法制备Fe75Si25纳米晶合金粉末，研究了高能球磨下的反应进程及产物，并讨论了合金粉末的微观结构和磁性能。结果表明：对于Fe75Si25粉末，合金化得到的是bee晶体结构的α-Fe（Si）固溶体。球磨84h以后，晶粒度达到了18nm，并且合金化程度较高。合金粉末具有良好的软磁性能，粉末的磁导率和比磁化强度，随着球磨时间的增加呈先减小后增大的趋势。热处理温度对粉末磁性能有着较大的影响，在380℃左右合金粉末的磁性能最好。     

铁基多元纳米晶合金的微组织和软磁性能

研究了新近开发的纳米晶（Fe90Zr3.5Nb3.5B3）95Cu1Si4合金的微组织和软磁性能.采用XRD、TEM和Mssbauer谱仪观察了合金的微组织变化,采用直流软磁测量设备测量了软磁性能.结果显示,合金是纳米晶相、残余非晶相和中间相的混合.软磁性能随着退火温度的变化而变化,且中间相的体积分数会影响软磁性能.当813K退火0.5h后,纳米晶相体积分数为40%,软磁性能最佳,此时BS最大为1.56T,HC达到最小为1.79A/m.     

快淬磁各向异性SmCo5的结构和磁性

采用熔体快淬法 ,在不同辊速条件下制得 Sm Co5合金条带。通过 X射线衍射和振动样品磁强计等手段对其结构和磁性进行研究。研究发现快淬带主要由 Ca Cu5结构的 Sm Co5相组成 ,在低辊速 (v=5 m/ s)条件下制得的快淬带经 90 0℃ / 2 h退火后 ,能获得高磁性能 :Mr=0 .91T,Mr/ Ms=0 .9,i Hc=12 96 k A/ m,(B· H) max=145 .6 k J/ m3 。     

Mn含量对Fe-Mn合金组织及力学性能的影响

利用扫描电镜、透射电镜、背散射电镜及拉伸和冲击试验研究了锰对含锰量为3%~12%的Fe-Mn合金组织和力学性能的影响。结果表明,当锰含量介于3%~9%时,随着锰含量的上升,高温相变产物(多边形铁素体和准多边形铁素体)受到抑制,合金的屈服强度和抗拉强度逐渐增加而均匀延伸率和总延伸率逐渐下降;当锰含量增加至12%时,合金中残留的少量亚稳ε马氏体和奥氏体在形变初期发生相变,产生的相变塑性使合金呈现出屈服强度下降的假象,但合金的抗拉强度、均匀延伸率和总延伸率均上升。由于晶界锰原子浓度的增加会减弱界面的结合力,故合金的冲击韧性随锰含量的增加而显著下降。为使Fe-Mn合金获得较好的综合力学性能,应控制锰含量小于7%或在基体中引入适量的亚稳相。     

Fe对AZ91镁合金热速处理组织和性能的影响

利用熔体热速处理工艺(TRT)和普通熔炼工艺(CM),研究了Fe对AZ91镁合金热速处理组织、性能的影响。结果表明,采用将合金液过热至液相线以上200～300℃的热速处理工艺时,合金基体明显细化,改善了合金的力学性能。随着Fe含量的增加,热速处理后枝晶组织不但没有细化,大量显微缩松的出现影响了合金的力学性能。     

Nd11Fe71Co8V1.5Cr1B7.5合金结构与磁性能的研究

采用熔体快淬及晶化处理工艺制备Nd11Fe71Co8V1.5Cr1B7.5纳米晶合金. 运用XRD, DTA等方法研究了快淬工艺与热处理工艺对该合金纳米晶形成、晶化过程及磁性能的影响. 结果表明, 快淬速度和热处理温度都明显地影响Nd11Fe71Co8V1.5Cr1B7.5纳米晶的形成及其磁性能; 该合金在晶化过程中先后出现了3个放热峰, 分别对应软磁相α-Fe, 亚稳相和硬磁相Nd2Fe14B 3个晶化相. 快淬速度21 m*s-1制备快淬薄片经640 ℃/4 min晶化处理后, 制成的粘结磁体的最佳磁性能为 Br=0.64 T, JHc=903.5 kA·m-1, (BH)max=71 kJ·m-3.     

镱对铝-镁合金显微组织和力学性能的影响

研究了Yb对Al-Mg合金显微组织和力学性能的影响.结果表明:添加0.3%(质量分数)Yb降低了Al-Mg合金的抗拉强度和屈服强度,主要是由于含Mg和Yb的化合物相的形成降低了Mg和Yb在Al基体中的固溶度,从而减小固溶强化效果.但添加1.0%Yb,基体中Yb溶质原子的浓度提高,产生很强的固溶强化效果,并提高热挤压制品的位错密度和加工硬化程度,改善合金的屈服强度和抗拉强度.     

Fe、Si杂质对7050合金组织及性能的影响

简述Fe、Si杂质在7050合金制品不同生产工序中的存在形式及其对7050合金显微组织及力学性能的影响.     

钨含量对Mo-W合金板材组织及力学性能的研究

Mo-W合金因为高熔点、低电阻率及优良的高温性能,在工业高温炉、电子光源和平板显示等诸多领域中已得到广泛应用.研究通过采用粉末冶金及轧制变形的工艺制备出Mo-W合金板材,研究了添加不同钨含量对Mo-W合金板材退火组织形貌演变及高温力学性能的影响.结果表明:轧制变形后的Mo-W合金板材与通过理论计算得到的密度值基本一致,...     

Effect of Zirconium Content on Microstructure and Magnetic Properties of Nanocomposite Bonded Magnets

Five kinds of bonded magnets with compositions of Nd10.5Fe78.4-xCo5ZrxB6.1(atom percentage x＝0,1.0,1.5,2.0,2.5)were prepared by rapid quenching, post heat treatment and mould-pressing.The microstructure and crystallization behavior were studied by X-ray diffraction (XRD), differential thermal analysis (DTA) and atomic force microscopy (AFM). The results suggest that high content of Zr can increase the glass formation ability (GFA) of alloys. When the content of Zr is controlled at a certain level, Fe2Zr with high melting point is formed in the alloys, and grain size is reduced consequently. At the same time, because of Zr addition, the coercivity and squareness of demagnetization loop are obviously improved, and the energy product is accordingly increased. As a result, optimal magnetic properties of Nd10.5Fe78.4-xCo5ZrxB6.1(Br＝0.659 T,Hcj＝628 kA·m-1,Hcb＝419 kA·m-1,(BH)m=73 kJ·m-3) are obtained when x=2.     

旋转磁场调控优化Cu-Cr-Zr-Si合金组织和性能

凝固过程是金属材料制备的核心环节,该过程决定了金属的铸态组织及性能。本文以Cu-Cr-Zr-Si合金为研究对象,对其施加旋转磁场,研究了真空下不同磁场电流对Cu-Cr-Zr-Si合金的凝固组织和性能的影响。组织结果表明,随磁场电流增大,晶粒尺寸减小。当磁场电流从40 A增加至120 A,基体的晶粒尺寸从270 μm细化至58 μm。此外,还观察到晶粒形貌逐渐从柱状晶转变为等轴晶,随磁场电流增大,等轴晶区域占比逐渐增加。性能分析表明：相比于未加磁场的合金,在磁场电流 I=40,80 和 120 A 条件下,合金抗拉强度分别提高了 6.1%,7.3%和19.2%;屈服强度提高了6.1%,10.%和19.4%;伸长率则分别提高17.4%,26.1%和60.9%。强度和塑性的提高主要归因于晶粒细化和等轴晶粒占比的提高。合金电导率在很大程度上不受旋转磁场的影响。在凝固过程中施加旋转磁场被认为是调控微观组织实现性能提高并可规模化生产的关键技术。     

Effect of Pulsed Magnetic Field on Microstructure and Mechanical Properties of Eutectic Al-Si Alloy

Pulsed magnetic field (PMF) processing has been employed for refining the microstructure of eutectic (Al-12.4Si) Al-Si alloy in the current study. The effect of PMF on microstructure and mechanical properties of eutectic Al-Si alloy was studied. The results show that the morphology of primary α-Al was refined from coarse columnar dendrites to fine equiaxed dendrites by PMF treatment. Fine short rod-like or rounded particle-like eutectic silicon was formed during solidification of eutectic Al-Si alloy treated by PMF. PMF treatment reduced the size of eutectic silicon from 49 to 2.3 μm in length, and the width from 3.1 to 0.6 μm. The aspect ratio of eutectic silicon was also reduced by PMF treatment from slightly less than 16 to slightly less than 4. The ultimate tensile strength and elongation of eutectic Al-Si alloy with PMF treatment at room temperature were about 201 MPa and 8.8 pct, respectively, which were increased by 47 and 73 pct, respectively, compared with the eutectic Al-Si alloy without PMF treatment.     

碳含量对K423高温合金组织及性能的影响

本文研究了碳元素对K423高温合金组织及性能的影响.结果表明,随着碳含量的增加,室温拉伸强度变化不大,塑性有所降低.850℃拉伸强度变化亦不明显,而屈服强度略有增加.850℃、325 MPa条件下随着碳含量的增加,持久寿命升高,塑性也有所增加.在850℃下,合金的组织会发生变化,而碳含量的增加,增强了K423合金的组织稳定性,抑制了有害相的析出.金相观测结果也表明,铸态下,本成分合金都未发现TCP相.经850℃热处理一定时间后,发现有σ相析出,且随电子空位数的增加,析出的σ相数量也增多.本文还利用电子空位数理论对不同合金成分进行了计算,碳含量升高,合金电子空位数降低,即合金的组织稳定性增强.综合力学性能测试结果、金相观测和电子空位数计算的结果可看出,适当提高合金的碳含量有益于K423合金性能的提高.     

Ti含量对热轧带钢组织和力学性能的影响

以普通集装箱板的成分为基础,在CSP生产线上成功开发出Ti微合金化高强度钢,采用扫描电镜、透射电镜、化学相分析等实验手段研究了Ti含量对带钢组织和性能的影响.结果表明:Ti含量变化对铁素体晶粒尺寸影响不大;随钢中Ti含量增加,TiN粒子的尺寸增大,TiC的体积分数增加,而TiC粒子的平均尺寸减小.在Ti含量为0.106%的钢中发现大量尺寸小于5 nm的细小析出物,正是这些析出物的沉淀强化作用显著提高了钢的强度.