镁基复合材料的低温超塑性

超细晶粒金属材料 (晶粒粒径 <10 μｍ)通常都具有很高的拉伸延性 (超塑性 )。准单相合金在较低应变速率 (<10 - 3ｓ- 1)和大约 0 8Ｔｍ(合金熔点 )的温度下可显示超塑性。对镁基合金的高应变速率超塑性进行了广泛的研究 ,在高温 (～ 6 2 3Ｋ)下也表现出高应变速率超塑性。降低变形温度 ,有利于减少能量消耗、减轻表面氧化并防止合金元素的选择贫化。有关镁基复合材料的低温超塑性行为的研究 ,至今几乎没有报道 ,因此 ,日本的大阪城市技术研究所研究了镁基复合材料的低温超塑性行为。研究用的材料是用 17% (体积 )ＳｉＣ颗粒增强的ＺＫ6 0…     

原位生成Al_3Zr/6063Al复合材料的高应变速率超塑性（英文）

采用熔体直接反应法,原位制备5%Al_3Zr/6063Al质量分数复合材料。在450℃进行70%变形量锻造预处理,然后进行搅拌摩擦大塑性加工,通过XRD、SEM、EDS、超景深及TEM等分析测试方法研究其高应变速率超塑性。结果表明,通过锻造和搅拌摩擦加工处理后,复合材料的平均晶粒尺寸小于10μm。在350~500℃,初始应变速率为1.0×10~(-3)~1.0×10~(-1)s~(-1)范围内,复合材料均呈现超塑性。在500℃,初始应变速率为1.0×10~(-2)s~(-1),延伸率达到最大值330%,反应敏感指数m值为0.45。分析超塑性变形的主要机制是动态连续再结晶与晶界、位错滑移共同协调完成。     

搅拌摩擦处理Al3Zr/6063原位复合材料的组织和性能

研究搅拌摩擦加工工艺对Al3Zrp/6063铝基复合材料组织性能的影响。该复合材料在6063-5%(K2ZrF6)体系下原位内生获得,利用OM、XRD、SEM观测原位内生颗粒Al3Zr的形貌、分布及尺寸,分析材料性能。实验分析可得:经搅拌摩擦处理后,复合材料的增强体更加细小均匀;基体晶粒破碎,晶粒形状发生改变;材料的抗拉强度变大,延伸率变大;具有超塑性,在变形温度500℃,应变速率1.67×10-2s-1,材料的延伸率达348.16%。     

连续柱状晶组织铜及铜合金的超延展变形行为与塑性提高机制

以本文作者所在课题组近年来的工作为基础,介绍了高性能连续柱状晶组织纯铜的室温超延展性、热交换用连续柱状晶组织BFe10-1-1管材的高塑性以及高弹高导Cu-12%Al(质量分数)合金的室温塑性提升。研究发现,连续柱状晶组织的高取向性、平直的低能小角晶界以及在强塑性变形过程中高组分的(001)软取向织构及不同于普通多晶组织的动态回复、组织演化特征,是其塑性提升、具有超延展变形能力的主要原因,总结了连续柱状晶组织塑性提高与超延展变形性的相关机制。研究结果为改善材料尤其是脆性材料和难加工材料的室温塑性与可加工性能提供了理论依据和新思路。     

铝基和钛基复合材料的塑性与超塑性

综述了近年来铝基和钛基复合材料的塑性和超塑性研究进展 ,分析了材料制备工艺和变形温度等参数对于复合材料的塑性和超塑性的影响规律 ,并展望了两种复合材料塑性和超塑性研究的发展方向。     

TC4钛合金板的超塑性

通过拉伸法和金相分析研究了国产TC4合金板的超塑性。结果表明:TC4合金超细晶粒板是一种优良的超塑性板材,不需其它处理即可用于超塑性成形;最佳超塑性成形条件是:变形温度为880～920℃,应变速率为5.5×10~(-4)S~(-1)～1.3×10~(-3)S~(-1),在此条件下,单向拉伸的m值为0.58～0.62,试件伸长量可达1000%以上;在最佳变形条件下,材料的变形抗力小于4kg/mm~2。     

超超临界转子用镍基材料的探索性研究

根据国际上关于超超临界转子镍基材料研究的最新进展,选定Inconel625、Inconel617及Nimonic263这三种成分合金进行了研究,热压缩实验结果表明,Nimonic263属于变形抗力较大的合金,Inconel625是最适于锻造成型的,较适宜的锻造温度为1 000～1 150℃。     

喷射成形超高碳钢的超塑性等温锻造性能研究

研究了喷射成形超高碳钢的显微组织 ,表征了其超塑性变形的力学特征 ,喷射成形超高碳钢的最佳变形温度为 82 0℃ ,最佳应变速率为 2 5× 10 - 4s- 1 。测定了超塑性等温锻造后喷射成形超高碳钢的室温力学性能 ,并观察了其显微组织。结果表明 ,超塑性等温锻造工艺使超高碳钢的组织得到了致密化 ,其原始组织主要是均匀、细密的珠光体 ,锻造后则大部分转变为细小的等轴铁素体晶粒以及弥散分布于其上的碳化物的组织。     

细晶Ti-17粉末合金的超塑性变形机制研究

采用粉末热等静压+等温锻造复合工艺制备出细晶Ti-17粉末合金材料,并研究了粉末合金在不同条件下的超塑性变形特性。结果表明:粉末热等静压+等温锻造复合工艺可制备出细晶Ti-17粉末钛合金,合金退火后组织内部等轴α相细小。在780~920℃以及应变速率5×10~(-4)~1×10~(-2)s~(-1)内粉末合金都具有超塑性。粉末合金超塑性变形是以晶界滑动为主,以扩散蠕变和晶内位错滑移为辅。孔洞的形核、长大和连接是导致粉末合金超塑性变形失效的主要原因。     

Ti-55钛合金超塑性板材的显微组织与力学性能

将二次真空自耗熔炼的Ti-55钛合金铸锭轧制成1.2mm厚的薄板,研究Ti-55钛合金超塑性板材的显微组织与力学性能。结果表明,显微组织均匀,晶粒极细的Ti-55钛合金超塑性板材,具有良好的室温拉伸性能和超塑性能。超塑性拉伸试验表明,在一定的变形温度范围(880～920℃)与变形速率(1.4×10~(-3)s~(-1))下,Ti-55钛合金板材超塑性伸长率可达到700%以上。     

Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2气氛下的腐蚀

研究了600℃时Fe-15Ce合金在H2-CO2、H2-H2S及H2-H2S-CO2 3种气氛中的腐蚀行为，Fe-15Ce合金腐蚀后发生了Ce的内氧化或形成了复杂的腐蚀产物膜，而未出现Ce的选择性氧化或硫化，这主要是合金中存在着两相及Ce在Fe中极低的溶解度的结果。Fe-15Ce合金在本实验条件下的氧化-硫化腐蚀速度低于相同温度、压力下的纯硫化。     

用氢-氧取代氧-乙炔作焊接切割的必要性及可行性

阐述了用氢代乙炔的必要性．通过时HGQU2000／315火焰电孤焊割机的考察和试用证实了用氢代乙炔的可行性，比较了两种气体的性质并提出了使用特性差异和注意事项．提出了进一步探索的问题。     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极制备及性能

通过热分解法制备了含IrO2-MnO2中间层Ti/RuO2-TiO2-SnO2电极,采用SEM、EDX、XRD、CV等检测方法对中间层进行表征,同时采用强化加速寿命试验对电极电化学稳定性进行表征。结果表明:450℃时前躯体完全氧化并形成固溶体,制备的中间层晶粒细小,表面结构致密,电化学孔隙率小。添加中间层使Ti/RuO2-TiO2-SnO2电极强化寿命由未加中间层的7.5h提高到995.8h,远高于国家标准20h。     

ACTIVITY OF La_2O_3 IN LIQUID La_2O_3-CaF_2 AND La_2O_3-CaF_2-CaO-SiO_2 SLAGS

用石墨为还原剂,将渣中La_2O_3还原入液态Sn,以测定1500℃下La_2O_3-CaF_2和La_2O_3-CaF_2-CaO-SiO_2渣中La_2O_3的活度.对La_2O_3-CaF_2系,并用Gibbs-Duhem积分法求得CaF_2的活度. 根据液态渣的离子结构模型,对上述二渣系中La_2O_3的活度数据进行了简单的讨论.     

Mechanoluminescence in BaSi2O2N2:Eu

Mechanoluminescence (ML), a general term for the phenomenon in which light emission occurs during any mechanical action on a solid, can be divided roughly into two classes: destructive ML and non-destructive ML. For practical use in high-end applications (e.g. pressure sensors), materials with non-destructive ML properties are preferred. This paper reports on the strong non-destructive ML in BaSi₂O₂N₂:Eu. When irradiated in advance with ultraviolet or blue light, this phosphor shows intense blue-green light emission upon mechanical stimulation such as friction or pressure. The ML has an emission band peaking at 498 nm, which is ～4 nm red-shifted compared to the steady-state photoluminescence. The origin of the ML is discussed and related to the persistent luminescence of BaSi₂O₂N₂:Eu. The same traps are responsible for both phenomena. Based on the occurrence of ML in this phosphor, we were able to show that the predominant crystallographic structure of BaSi₂O₂N₂:Eu belongs to space group Cmc2₁.     

氢分子在贮氢材料Li2MgN2H2表面的吸附与解离

采用第一性原理计算方法研究了Li-Mg-N-H体系贮氢材料的放氢产物Li2MgN2H2的吸氢反应过程中的过渡态、表面电子态密度和表面能。结果表明:氢分子在Li2MgN2H2低指数表面中最低能量(100)表面的Mg-Mg-Li穴位吸附位置能够形成最稳定的吸附结构并发生解离,氢分子吸附能为-0.1898eV,解离能约为0.84eV(81kJ/mol),表明该反应所需的反应活化能仍较高,吸氢反应速度缓慢。     

Thermodynamic evaluation of phase equilibria in the CaCl2-MgCl2-CaF2-MgF2 system

The phase diagram of the CaCl₂-CaF₂-MgCl₂-MgF₂ reciprocal ternary system was calculated thermodynamically from available data on the common-ion binary subsystems and from available data on the CaCl₂-MgF₂ join. This join is very nearly quasibinary and divides the system into two quasiternary systems: the CaCl₂-MgF₂-CaF₂ system with a ternary eutectic calculated at 724 +-5 °C and the CaC₂-MgF₂-MgCl₂ system with a ternary eutectic calculated at 561 +-5 °C.     

The Quasi-Ternary System Cu2Se-Ga2Se3-GeSe2

The quasi-ternary system Cu₂Se-Ga₂Se₃-GeSe₂ was investigated using the methods of differential thermal and x-ray analysis. An isothermal section at 770 K and a liquidus surface projection of the phase diagram were constructed. The existence of the quaternary phase CuGaGeSe₄, the boundaries of solid solutions ranges of the system compounds were established.     

High temperature corrosion of Fe-Cr-Mn-alloys in H2-H2S and H2-H2O-H2S gas mixtures

The sulfidation of Fe-20% Cr-30% Mn, Fe-25%Cr-20%Mn and Fe-25% Cr was studied at 700°C in H₂-H₂S and the oxidation and sulfidation in H₂-H₂O-H₂S after preoxidation in H₂-H₂O. The sulfidation rate is strongly increased for the Mn-containing alloys, layers of (Mn,Cr)S and (Mn,Fe)Cr₂S₄ are formed. Also the oxidation rate is enhanced compared to Fe-25% Cr by formation of MnCr₂O₄ instead of Cr₂O₃. The sulfidation after preoxidation leads to internal and external sulfidation of the Mn-containing alloys. With increasing oxygen pressure p(O₂) = 10^?26…10^?22 atm. of the H₂-H₂O-H₂S mixtures the sulfidation is suppressed, for the higher oxygen pressure 10^?23 and 10^?22 atm. fast oxidation prevails under formation of MnCr₂O₄. Manganese cannot increase the sulfidation resistance of alloys, in spite of the stability and low degree of disorder of its sulfide, since the mixed sulfide (Mn,Cr)S is formed which has a high degree of disorder, high diffusivities and high growth rate according to the doping effect of trivalent Cr³⁺.