ZrCuAlSi大块非晶合金形成及力学性能

通过铜模铸造法制备(Zr47Cu44Al9)100-xSix(x=0,0.5,1.5,2.5)大块非晶合金.利用差热分析、X射线衍射、显微硬度和室温压缩试验.研究分析添加Si元素对Zr47Cu44Al9合金非晶形成能力、热稳定性及力学性能的影响.结果表明,适量Si的加入能显著提高非晶合金的热稳定性,当Si的加入量为1.5时,合金具有最大的非晶形成能力,其纯非晶试样的临界尺寸由Zr47Cu44Al9的4 mm增大到(Zr47Cu44Al9)98.5Si1.5的6 mm.Si提高非晶形成能力的原因主要是抑制了引起异质形核的CuZr相的形成与析出.力学性能实验显示,显微硬度(Hv)随Si的加入由Zr47Cu44Al9合金的5850MPa增呔到(Zr47Cu44Al9)98.5Si1.5合金的6220 MPa,(Zr47Cu44Al9)98.5Si1.5合金的断裂强度为1862 MPa.     

Y含量对Zr_(47-x)Cu_(46)Al_7Y_x合金非晶形成能力及力学性能的影响

采用高真空电弧熔炼喷射成形法制备Zr_(47_x)Cu_(46)Al_7Y_x(x=3~8)大块非晶合金。采用X射线衍射分析、差示扫描量热仪、扫描电子显微镜、压缩试验和硬度试验分别研究Y含量对合金的非晶形成能力、显微组织、断口形貌及力学性能的影响。结果表明:Y含量对合金系的非晶形成能力和力学性能有显著影响,4 at%~7 at%Y含量试样由完全非晶组织构成,其过冷液相区ΔT_x为56~71 K,约化玻璃转变温度T_(rg)为0.665~0.678,但在3 at%与8 at%Y含量试样非晶基体中出现了极少量结晶组织。大块非晶具有较好力学性能,其抗压强度为1803~1899 MPa,维氏硬度为5.22~5.39 GPa,且具有较强非晶形成能力的试样相应地具有较好的力学性能。大块非晶在压缩中以纯弹性变形方式发生脆性断裂,断口光滑平整,为典型脉络状花纹。     

Zr-Cu-Al-Y非晶合金的制备及性能研究

采用铜模铸造法对Zr47-xCu46Al7Yx(x=3～7)非晶合金进行了研究,成功地制备出临界直径为6mm的Zr42Cu46Al7Y5四元大块非晶合金;研究了Y含量对非晶合金的形成和性能的影响.结果表明,压缩变形呈现弹性变形、脆性断裂特性,非晶合金的硬度随Y含量的增加而增加.该非晶合金具有较好的压缩断裂强度、维氏硬度以及良好的弹性.     

Gd含量对Zr48-xCu45Al7Gdx非晶形成能力与力学性能的影响

采用高真空电弧熔炼喷射成形法制备Zr48-x Cu45Al7Gdx(x=0～7)大块非晶。利用X射线衍射仪、差示扫描量热仪、扫描电子显微镜、压缩试验和硬度试验分别研究Gd含量对合金非晶形成能力,组织形貌与断口形貌和力学性能的影响。结果表明,Gd含量对合金系的非晶形成能力和力学性能有显著影响,Gd含量为(2～5)at%时,可制得直径4 mm大块非晶,非晶合金具有较大过冷液相区ΔTx(73～79 K),约化玻璃转变温度Trg(0.694～0.698)。合金由无特征非晶组织构成,抗压强度σb为1768～1794 MPa,HV硬度为5.08～5.32 GPa。压缩试验中,试样以纯弹性变形方式发生脆性断裂,断口光滑平整,为典型脉络状花纹。     

微量元素对Cu-Zr基合金非晶形成能力的影响

采用铜模喷铸成形法制备Cu50Zr50、Cu62-xZr38-xAl2x(2x=2at％、4at％和6at％)和Cu46Zr47-xAl7Yx(x=4at％ ～7at％)大块非晶试样.通过X射线衍射分析、扫描电子显微镜和示差扫描量热计(DSC)分别研究添加元素Al与Y对Cu-Zr二元合金非晶形成能力、显微形貌和热稳定性的影响.结果表明:所制备的Cu50Zr50、Cu61Zr37Al2为非晶合金,基体中含极少量结晶相,非晶形成能力对Cu-Zr-Al成分较为敏感;Y含量对直径为4 mm的Zr47-xCu46Al7Yx非晶形成能力和显微组织有着显著影响,Y含量4at％时,基体中含极少量结晶相,Y含量5at％ ～ 7at％时,非晶合金呈现完全无特征组织.     

半固态处理对(Zr_(0.60)Ni_(0.22)Al_(0.18))_(96)Fe_4合金非晶形成能力和力学性能的影响

将Fe元素添加到Zr-Ni-Al合金体系中,采用铜模吸铸法在不同电压下制备出直径为3 mm的(Zr0.60Ni0.22Al0.18)96Fe4圆棒合金试样。采用X射线衍射(XRD),扫描电子显微镜(SEM)、示差扫描量热仪(DSC)、微机控制电子式万能试验机和显微硬度计等设备测试了半固态处理对(Zr0.60Ni0.22Al0.18)96Fe4块体非晶合金的非晶形成能力和力学性能的影响。结果表明,10 kV吸铸的(Zr0.60Ni0.22Al0.18)96Fe4试样为完全非晶结构,合金具有较强的非晶形成能力,其过冷液相区宽度ΔTx可以达到78 K,约化玻璃转变温度Trg(Trg=Tg/Tm)可达0.632;电压8 kV时吸铸制得的(Zr0.60Ni0.22Al0.18)96Fe4合金由非晶主相和少量FeZr2晶体相组成,其断裂强度σf为2 077 MPa,显微硬度为720 HV,塑性应变量εp为1.7%;随吸铸电压适量降低,7 kV吸铸时,合金仍为非晶/晶体复合材料,但晶体相份额增多,合金的强度和硬度提高。     

铝含量对(Zr_(0.761)Cu_(0.147)Ni_(0.092))_(93-x)Al_(7+x)非晶合金的热稳定性及其力学性能的影响

采用铜模吸铸法制备(Zr_(0.761)Cu_(0.147)Ni_(0.092))_(93-x)Al_(7+x)(x=0,1,2,3,5,7(摩尔分数,%))块体非晶合金,采用同步示差扫描量热仪(DSC)、万能试验机和显微硬度计测试各试样的过冷液相区、压缩塑性和显微硬度,利用X射线衍射(XRD)和扫描电镜(SEM)等手段对其微观结构和力学性能的关系进行分析。结果表明:随着Al含量的增加,(Zr_(0.761)Cu_(0.147)Ni_(0.092))_(93-x)Al_(7+x)非晶合金的玻璃转变温度T_g、初始晶化温度T_x均呈现增大的趋势,而过冷液相区ΔT_x先增大后减小,在x=3时达到最大的94 K。合金塑性变形ε_p随着Al含量的增加先增大后减小,在x=3时达到最大值为15.82%;合金屈服强度σ_s和显微硬度HV都呈现增强的趋势,在x=7时取得最大值,分别为1713和4095 MPa。     

Al含量对Zr-Cu-Ni-Al合金力学性能的影响

借助X-射线衍射仪、数字显微硬度计、扫描电镜和万能材料试验机等设备研究了Al含量变化对Zr合金力学性能的影响。结果表明,随着Al含量的增加,合金组织中的晶粒变小,合金硬度,压缩强度增加;当Al原子含量达到10%时,合金的硬度,强度都最佳;随着Al含量的进一步升高,合金力学性能下降。     

熔炼气氛中的氧含量对锆基非晶合金非晶形成能力及力学性能的影响

在氧气浓度(体积分数)分别为4.19％、0.838％、0.168％的熔炼气氛下熔炼成分为Zr63.36Cu14.52Ni10.12Al12的母合金,采用铜型吸铸法将其制备成非晶合金棒状试样,研究了合金的非晶形成能力与压缩力学性能的变化规律.结果表明:随着熔炼气氛中氧含量的减少,合金的晶化温度由653.7 K下降至645.1 K,过冷液相区宽度由85.8 K上升至94.3 K;非晶合金的最大抗压强度由1.82 GPa上升至1.94 GPa,塑性形变由2.29％提升至18.99％;随着氧含量的降低,Zr63.36Cu14.52Ni10.12Al12合金的非晶形成能力上升,力学性能得到提高.     

Gd的添加对Cu基块体非晶玻璃形成能力、热稳定性及压缩性能的影响(英文)

为研究铜基块体非晶的塑性以及稀土元素对其力学性能的影响,采用悬浮熔炼-铜模吸铸法制备了直径为3mm、成分为Cu50-xZr42Al8Gdx(x=0,2,4)的合金圆棒。利用X射线衍射(XRD)和差示扫描量热法(DSC)分别对合金的结构和热稳定性进行了测定。并通过对试样压缩性能测试以及断口形貌的观察,研究了添加稀土元素Gd对Cu基块体非晶的力学性能及断裂行为的影响。结果表明:Cu50-xZr42Al8Gdx(x=0,2,4)合金圆棒的结构为明显的非晶相,试样具有较高的热稳定性和较好的玻璃形成能力。随着稀土元素Gd含量的增加,Cu基块体非晶的脆性逐渐增强。断裂方式均为脆性断裂。     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.     

面向零件形状的计算机图形库的开发

论述了CAD技术中参数化设计的三种建模方法，重点介绍了基于特征的参数化建模原理。在此基础上，分析机械设计中的机构结构，归纳出其零件的几何特征构成。设计了机构CAD图形库，并提出了该图形库生成步骤和人机交互界面。