Preparation and Characterization of Fe2O3/Al2O3 Nano-composites

Al2O3/Fe2O3 nano-composites were prepared by sol-gel route. The effect of Fe2O3content on the structure, grain size and characterization of the composite were investigated through X-ray diffraction and Mssbauer spectrum. The X-ray diffraction results show that Al2O3/Fe2O3 nano-composites with the Fe2O3content of 40 wt% can be obtained after heat-treated at 900 ℃. The Mssbauer effect results show that all samples exhibit clear super-paramagnetic phenomenon. Particles grow and defects reduce with the increasing of Fe2O3content and some α-Fe2O3stay magnetic order.     

M(o)ssbauer and electron microscopy study of martensitic transformations in an Fe-Mn-Mo alloy

The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt%Mn-5.2wt% Mo alloy were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and M(o)ssbauer spectroscopy.The experimental results reveal that two types of thermal-induced martensites,ε(hcp)and αˊ(bcc)martensites,are formed in the as-quenched condition,and these transformations have athermal characters.Mo addition to the Fe-Mn alloy does not change the coexistence of ε and αˊ martensites with the Mn content between 10wt% and 15wt%.Besides,M(o)ssbauer spectra reveal a paramagnetic character with a singlet for the γ(fcc)austenite and ε martensite phases and a ferromagnetic character with a broad sextet for the αˊ martensite phase.The volume fraction of αˊmartensite forming in the quenched alloy is much more than that of the ε martensite.     

Effects of heat treatment on the microstructure and mechanical properties of ZA84 magnesium alloy

The effects of heat treatment on the microstructure and mechanical properties of ZA84 (Mg-8Zn-4Al-0.25Mn) alloy were investigated. The results indicate that the as-cast microstructure of the alloy is mainly composed of α-Mg matrix and two different morphologies of precipitates (continuous and quasi-continuous Mg32(Al,Zn)49 phases and isolated Mg5Al2Zn2 phases). After solid solution treatment at 345°C, the Mg32(Al,Zn)49 phases change from continuous and quasi-continuous net to disconnected acute angle shape,...     

置氢TC4钛合金等温锻造叶片组织演变规律

为了降低钛合金叶片的锻造温度和改善其组织性能,基于氢致钛合金高温增塑机理,将热氢处理技术应用于钛合金叶片的等温锻造成形工艺中.观察和对比分析了未置氢TC4钛合金和置氢TC4钛合金叶片等温锻造后的组织以及真空除氢热处理和普通热处理工艺下的组织演变.实验结果表明:置氢降低了TC4钛合金叶片的等温锻造载荷,除氢热处理后组织得到改善,获得了含有细小、等轴α晶粒的双态组织.确定了置氢量为0.25%(质量分数)的TC4钛合金适宜的热处理工艺为:锻后在750℃真空脱氢保温5h,900℃退火1h后再450℃时效4h.     

Effects of heat treatment process on thin film alloy resistance and its stability

1　INTRODUCTIONSensortechnologyisveryimportantininforma tionacquisitionandprocessingtechniquefields ,fromcosmicexplorationtooceanicexploitation ,andfromproductioncontrollingtomodernizedlife .Sensors ,withgreatprospect ,havebeencomprehensivelyap pliedinmanyfields ,suchasindustry ,agriculture ,nationaldefenseandsoon .Almosteverynationat tachesmuchimportancetothedevelopmentofsensortechnology ,andJapanlistsitasoneofthesixkeytechnologies[1] .Sensortechnologyisalsolistedas“theNinthFive” ,“t…     

涂覆纳米TiO2薄膜的自洁玻璃研究

采用溶胶—凝胶法,并用浸渍提拉技术制备了涂覆纳米TiO2薄膜的自洁玻璃。通过热分析讨论了凝胶的转变过程。对比了自洁玻璃的亲水性,研究了该样品的光催化性能。研究表明,干凝胶的最佳热处理制度为升温速度为12℃／h．450℃时保温1h;镀膜6次的试样具有最好的光催化能力;样品在日光照射下也具有良好的亲水性和一定的自洁性能,但是,在可见光（不含紫外线）的照射下．没有体现出明显的亲水性和自洁性能。     

微量Hf对变形TiAl合金组织和力学性能的影响

对比观察含Hf和不含Hf的TiAl合金的变形组织和热处理组织，发现在1310℃／1h／AC热处理后均获得近全层片组织，平均晶粒尺寸为50～70μm，γ相的体积分数为12％左右；退火温度升高至1320℃，则均获得了全层片组织，平均层片团尺寸为200～300μm．在同为近全层片组织下进行力学性能试验发现：添加合金元素Hf，使TiAl合金800℃高温拉伸强度提高60MPa和800℃，150MPa应力持久寿命由84h提高到128h．     

去应力退火对DZ125合金再结晶行为的影响

为了获得具有优异高温力学性能的定向凝固高温合金,减少定向凝固叶片在生产过程中产生再结晶的现象,对经过喷丸后的DZ125合金进行了去应力退火处理,随后对其进行了不同温度下的热处理.利用扫描电子显微镜观察了DZ125合金的微观组织.结果表明,当表征喷丸强度的Almen值为0.25 mm时,依次进行870℃/500 h去应力退火与1 000℃/4 h热处理后,DZ125合金中仍存在少量胞状再结晶.经过1 150℃/4 h热处理后,胞状再结晶层厚度约降低30%;经过1 230℃/4 h热处理后,等轴状再结晶层厚度总体约降低了30%.当Almen值为0.17 mm时,在870℃下进行不同时间的去应力退火处理与1 230℃/4 h热处理后发现,随着退火时间的增加,再结晶层厚度逐渐降低,当退火时间为500 h时,再结晶层厚度约降低50%.     

新型环三磷腈衍生物的合成及表征

以六氯环三磷腈（HCCP）、新戊二醇（NPG）和金属钠为原料,制备一种新型环三磷腈阻燃剂三（2,2-二甲基-1,3-丙二氧基）环三磷腈（TDPCP）。采用傅里叶红外光谱、核磁共振氢谱、核磁共振磷谱、元素分析和热重对产物的结构和热性能进行了表征,并探究了反应溶剂、反应物投料比、反应温度和反应时间对TDPCP收率的影响。结果表明:以四氢呋喃为溶剂,n（HCCP）∶n（NPG）=1∶4.5,70?℃回流反应24?h,TDPCP收率可达85.5%;产物结构与TDPCP相一致;TDPCP的初始分解温度为243?℃,800?℃的残碳量为14.6%,是一种耐热性和稳定性较好的杂环化合物。     

纳米Fe-Cu体系的结构和电阻温度特性

采用机械合金化方法制备了亚稳Fe50Cu50纳米合金粉末,压片后在氩气中分别进行523 K、873 K热处理。利用X-ray衍射和M ssbauer效应对样品的结构和相变进行了分析,结果表明,机械合金化后的样品为面心立方结构的固溶体,经523K热处理后,亚稳合金已开始分解;经873 K热处理后,样品已完全转变为纳米尺寸的α-Fe和Cu的混合体。在15~295 K内对热处理后样品的电阻进行了测量,结果表明,样品表现为负的电阻温度系数。     

Properties of biogenic magnetite nanoparticles in the radula of chiton <Emphasis Type="Italic">Acanthochiton rubrolineatus</Emphasis> lischke

The properties of biogenic magnetite(Fe 3 O 4 )nanoparticles in chiton acanthochiton rubrolineatus lischke were characterized by selected electron diffractometry,high resolution transmission electron microscopy,Fourier transform infrared spectroscopy,M·ssbauer spectroscopy and magnetization measurements.Results showed that the magnetite nanoparticles presented crystalline appearance,exhibiting strong absorptions at 595,1 463,3 467 cm-1 and weak adsorptions at 1 697,1 113,1 048,848,445 cm-1 in FT-IR,two partially overlapping sextets in M·ssbauer spectrum,and the area ratio of the sextets was 1.08.Also,the particles exhibited ferromagnetic behavior,and had 82 A·m2/kg saturation magnetization,1.4·104 A/m coercive force and 4.0 A·m2/kg remnant magnetization,respectively.The investigation indicates that the biogenic magnetite nanoparticles mineralized in the chiton are impure in composition and non-stoichiometric.     

锅炉受热面钢材离子硼钼共渗后耐磨性能试验研究

研究了电厂锅炉受热面常用合金钢12Cr1MoV表面离子硼钼共渗处理后,在300～450℃的耐热态飞灰冲蚀磨损性能.试验结果表明:经离子硼钼共渗处理后的12Cr1MoV耐磨性能有所提高,并且其磨损规律仍呈现热态规律.用电镜扫描(SEM)和辉光放电光谱分析仪对试件进行渗层分析表明,试件表面渗层的元素组成及其含量对材料耐磨性能有较大的影响.     

Moessbauer spectra of MnFe2-2x Al2xO4 （0 ≤x≤ 0.4） ferrites

The effect of non-magnetic Al³⁺ ion doping on the magnetic properties of MnFe_2−2x Al_2x O₄ (0≼x≼0.4) spinel ferrites was studied using M?ssbauer spectroscopy measurements at room temperature. From the M?ssbauer study, it is observed that the resolved hyperfine sextets are due to the distribution of Fe ions on the two sublattices of the spinel ferrites. The value of the isomer shift obtained from the fitting of the M?ssbauer spectra indicates that Fe ions are in +3 state. A paramagnetic doublet is observed at degree of inversion x=0.4, superimposed on the hyperfine sextets, indicating that the super-exchange interaction A–B decreases due to the dilution of sublattice by Al³⁺ ions. The hyperfine magnetic field decreases at both interstitial sites of tetrahedral (A) and octahedral (B) with the increase in Al concentration.     

喷射沉积含Sc超高强铝合金固溶处理组织与性能分析

采用金相、扫描电镜、X射线衍射分析方法,研究了不同工艺条件下喷射沉积Al-12Zn-2.4Mg-1.1Cu-0.20Zr-0.30Sc-0.30Ni合金的微观组织与力学性能.结果表明,过喷粉颗粒的大小为3~15μm,是沉积坯等轴晶平均直径的1/6~3/4;挤压坯经460℃/0.5 h+480℃/2 h二级固溶处理后Zn,Mg,Cu等溶质元素回溶到Al基体中,固溶后未见形成W(ScCu6.6~4Al5.4~8)相,合金抗拉强度由挤压态的410 MPa增加到固溶态的750 MPa,增幅为82.9%;再经T6时效后合金的抗拉强度可达855 MPa.凝固过程形成的粗大难溶DO23结构Al3(Sc,Zr)粒子是影响合金抗拉强度的重要原因.     

Microstructure and mechanical property of 2024／3003 gradient aluminum alloy

2024/3003 gradient aluminum alloy was prepared by semi-continuous casting using double-stream-pou-ring technique. The microstructures of the as-cast, pressed and heat-treated alloys were analyzed by scanning elec-tron microscope and transmission electron microscope. And the mechanical properties of the alloy in pressed and heat-treated states were studied. The results show that the ingots with diameter of 65 mm and external thickness about 5.5 mm are obtained when the temperatures of the melt in the internal and external ladles are 1 023 and 1 003 K, respectively, and the nozzle diameter is 2.0 mm. The microstructures of the as-cast alloy consist of α(AI) θ(CuAl2)q S(Al2CuMg) in the internal region and α(Al) MnAl6 in the external region. The phases found in the internal and external layers coexist in the transition zone. The transition layer is maintained after plastic deformation and heat treatment of the alloy. The tensile strength, yield strength and elongation of the alloy are 300 MPa,132 MPa and 16.0%, respectively, after T6 treatment. The tensile and yield strength are increased by 150.0% and 94.1%, respectively, compared with that of 3003 aluminum alloy. The maximum hardness in the internal region of 2024/3003 gradient aluminum alloy can be increased from HRF 55 in the pressed state to HRF 70 in the heat-treated state.     

低频脉冲磁场处理Co_(68.15)Fe_(4.35)Si_(12.5)B_(15)的穆斯堡尔谱研究

用低频脉冲磁场处理非晶合金Co68.15Fe4.35Si12.5B15,用穆斯堡尔谱结合透射电镜对处理前后的试样进行了微结构分析。结果表明,在低频脉冲磁场处理下,非晶合金Co68.15Fe4.35Si12.5B15发生了纳米晶化,晶化析出相为体心立方α-Fe(Si),析出量为2.743%~23.960%,晶粒尺寸约2~10 nm,且晶化量与磁场强度和脉冲频率均有关系。     

热处理温度对CrMoNi铸铁基化学镀Ni-P层显微结构与性能的影响

采用化学镀技术在CrMoNi高合金铸铁表面沉积Ni—P合金镀层,采用维氏硬度仪、M-2000摩擦磨损机、SEM和EDAX等手段研究了热处理温度对Ni-P合金镀层组织结构和性能的影响,并对磨损机理进行了分析．研究结果表明：CrMoNi合金基体表面沉积Ni—P合金镀层能有效改善CrMoNi合金基体硬度和耐磨性．经过350℃热处理时,获得的Ni-P合金镀层硬度达到极值1072HV,为基体硬度的4．5倍,耐磨性最佳,磨损率仅为基体的0．68％o,镀层的磨损机制为轻微的黏着磨损．     

三种Mg—Gd—Y系合金显微组织分析

为了进-步研究不同热处理状态对Mg-Gd-Y系合金显微组织的影响,采用光学显微镜（（）M）、透射电子显微镜（TEM）和X射线衍射仪（XRD）分析了Mg-20Gd、Mg-20Y和Mg-9Gd-3Y合金恒温处理前后的微观组织与相组成．研究结果表明：Mg-20Gd、Mg-20Y和Mg-9Gd-3Y合金在室温的平衡态显微组织分别是0t-Mg＋GdMg5、0t-Mg＋Mg24Y5和a-Mg＋GdMg5＋Mg24Y5;实验合金在520℃8h＋300。C144h恒温处理后,Mg-20Gd合金中有平衡相GdMgs和非平衡相Mg3Gd,其中析出相为MgGds;Mg-20Y合金中有平衡相Mg2aYs,其中析出相是Mgz-Ys;Mg-9Gd-3Y合金中有平衡相GdMg5、Mg24Y5和非平衡相Mg2Gd,析出相为GdMg5与Mg24Y5．     

La0.67Mg0.33Ni2.5Cu0.5贮氢合金磁热处理工艺的正交设计

利用L9（34）正交表安排实验,考察磁热处理的温度、时间及磁感应强度对La0.67Mg0.33N i2.5Cu0.5合金的吸放氢反应热力学和动力学的影响,结合极差分析和方差分析研究了各因素对考核指标的显著性影响,并得到合金磁热处理的优化工艺：热处理温度850℃,处理时间1 h和磁感应强度4 T.在此条件下处理后的合金,吸放氢的质量分数分别为1.33%和1.14%,焓变为-59.69 kJ/mol,吸热峰顶所对应的温度为86.3℃,吸放氢特征时间（tξ=0.875）分别为11.2和108.7 s.结果表明,该合金与其它工艺下的样品相比,吸氢量最大,放氢后物相结构最稳定,吸热峰顶所对应的温度最低,吸放氢速度最快.     

Effect of heat treatment of Mn-Cu precursors on morphology of dealloyed nanoporous copper

Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method. The effects of heat treatment of Mn-Cu precursors on alloy phase, morphology and composition of the resultant nanoporous copper were investigated. It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors, which consequently results in a more fully dealloying for forming nanoporous copper. The alloy phase changes from Cu_0.49Mn_0.51 and Cu_0.21Mn_0.79 of non-thermally treated precursor to Cu_0.33Mn_0.67 of heat treated alloy. The residual Mn content in nanoporous copper is decreased from 12.97% to 2.04% (molar fraction) made from the precursor without and with 95 h heat treatment. The typical pore shape of nanoporous copper prepared by dealloying the precursor without the heat treatment is divided into two different zones: the uniform bi-continuous structure zone and the blurry or no pore structure zone. Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated precursor, and the average ligament diameter is 40 nm, far smaller than that from the non-thermally treated precursor, in which the average ligament diameter is estimated to be about 70 nm.