钨合金动态力学性能研究进展

本文详细总结了钨合金动态力学性能的研究结果，其内容主要包括：（１）钨合金在高应变率载荷下的宏观响应以及不同应变率下力学性能的差异；（２）影响钨合金性能和应变率敏感因素，并指出了今后研究的方向。     

高强PVA纤维束冲击拉伸性能的实验研究

利用ＭＴＳ和旋转盘式杆－杆型冲击拉伸试验装置，在高应变率、大应变率范围条件下９０．０１￣１５００ｓ＾－１）研究了应变率对高强ＰＶＡ纤维束力学性能的影响；同时，利用扫描电子显微镜考察了纤维材料在不同应变率下的微观断裂机理。     

纤维混凝土动态压缩力学性能的实验研究

利用SHPB（split Hopkinson pressure bar）压杆，采用改进的实验技术对钢纤维混凝土和聚丙烯纤维混凝土进行了动态压缩力学性能实验，通过实验得到不同应变率下的应力-应变曲线，初步讨论了纤维掺量对混凝土的增韧效应、应变率效应、动态弹性模量的影响。     

脉冲电流对Zn－22Al合金超塑性力学行为的影响

本文以普通处理的Ｚｎ－２２Ａｌ合金板坯为对象，研究了脉冲电流对其超塑性力学行为的影响．实验结果表明：在脉冲电流作用下，合金的延伸率和应变速度敏感性指数有了很大提高，流动应力降低．在高应变速率（３．３×１０（－２）ｓ（－１））下，该合金仍具有很高的延伸率．最佳超塑变形温度向低温度方向偏移．合金的超塑变形可在更低温度下进行．     

V-5Cr-5Ti合金的动态压缩力学性能及本构关系

利用Hopkinson压杆技术对V-5Cr-5Ti合金动态压缩力学性能进行了实验测试,获得了不同应变率下V-5Cr-5Ti合金的压缩应力—应变曲线,结果显示V-5Cr-5Ti合金具有较强的应变率敏感性。根据实验结果,确定了描述V-5Cr-5Ti合金常温动态性能本构参数,并将实验结果与计算结果进行了比较,两者吻合较好。     

W-Ni-Fe-Cu体系钨合金的液相烧结与低温致密化

采用三元烧结剂Ni-Fe-Cu在低温下（1 573 K）进行了钨合金的液相烧结研究。通过加入2wt%Cu,在1 573 K-30 MPa-90 min的热压条件下成功制备出几乎完全致密并具有较高抗弯强度的93W-3.5Ni-1.5Fe-2.0Cu合金,详细探讨了W-Ni-Fe-Cu体系钨合金的低温致密化机理。     

稀土Er对FVS0812合金组织性能的影响

为欲充分发挥ＡｌＦｅＶＳｉ系耐热铝合金应用潜力，进一步提高合金的综合性能。本文采用了金相，Ｘ射线衍射，透射电镜和力学性能等测试手段研究了稀土元素ＦＶＳ０８１２合金的显微组织，力学性能以及热稳定性的影响，结果表明，ＦＶＳ０８１２合金中加入少量Ｅｒ可以保持合金良好的高温强度，明显改善合金塑性，而且降低了主要强化相Ａｌ１２（ｆＥ，ｖ）３Ｓｉ硅化物的粗化率，提高合金的高温稳定性；     

20CrMnTi 温变形性能研究

对２０ＣｒＭｎＴｉ在（６５０～８５０）℃温度范围内进行的变形性能实验研究，给出了该材料温变形时的真实应力－应变曲线和低温形变热处理后工件力学性能与变形参数间的关系曲线；建立了该合金温变形时流变应力“峰值”与变形温度间的函数关系及低温形变热处理（淬火）后工件力学性能与变形参数间的关系式．结果表明，该材料具有良好的温成形性能；低温形变热处理可得到良好的力学性能．     

20CrMnTi温变形性能研究

对２０ＣｒＭｎＴｉ在（６５０￣８５０）℃温度范围内进行的变形性能实验研究，给出了核材料温变形时的真实应力－－应变曲线和低温形变热处理后工件力学性能与变形参数间的关系曲线；建立了该合金温变形时流变应力“峰值”与变形温度间的函数关系及低温形变热处理（淬火）后工件力学性能与变形参数间的关系式。结果表明，该材料具有良好的浊恩形性能；低温形变热处理可得到良好的力学性能。     

纳米添加剂对W—Ni—Cu合金性能的影响

研究了纳米添加剂对W-Ni-Cu合金性能的影响和作用机理；用扫描电镜和金相显微分析技术研究了合金的形貌与结构；测量了合金试样的物理力学性能．研究结果表明：加入纳米添加剂可降低烧结温度；选用的纳米添加剂对钨晶粒的长大起了抑制作用，细化了W-Ni-Cu合金的晶粒；适量的纳米添加剂大部分分布于Ni-Cu粘结相中．在该实验条件下，在1430℃烧结得到了全致密的W-Ni-Cu合金．     

Dynamic mechanical behavior and microstructural evolution of the Al-6Mg alloy subjected to three treatment conditions

The mechanical properties of Al-6Mg alloy with three treatment states (H112, O and cold-extruded states) were investigated at room and high temperatures using an INSTRON machine and a Split Hopkinson Pressure Bar (SHPB). Stress-strain curves of the alloy with different processes were obtained at a quasi-static strain rate of 5×10-4 s-1and dynamic strain rates of 1 400-4 200 s-1, respectively. The results suggest that, at room temperature, the three processed Al-6Mg alloys are all low sensitive to strain rate. The O state Al-6Mg alloy (Al-6Mg-O) exhibits the most ductility, while the cold-extruded Al-6Mg alloy (Al-6Mg-C) displays the highest strength. At elevated temperatures, the yield stresses and the differences in yield stress of the three processed alloys all decrease with increasing temperature under the quasi-static strain rate of 5×10-4 s-1. Based on test results, modified Johnson-Cook (JC) constitutive models for the three processed Al-6Mg alloys were developed. The microstructures before and after deformation were examined by electron backscattered diffraction (EBSD) and further dynamic recrystallization (DRX) at the strain rate of 3 300 s-1 was discussed.     

慢加载时拉伸速率与铸铝合金的力学性能

在研究了慢加载条件下拉伸速率与球墨铸铁间力学性能的关系后，将试验对象扩展到铸铝合金，结果证实，在ε＝10^-1-10^-4s^-1范围内，铸铝合金的力学性胡亦随拉伸速率的逐渐减慢呈峰状变化，即先逐渐增加，到某一最大后又逐渐降低，曲线的走向与球墨铸铁的相应曲线极为相似。     

Mechanical properties and microstructure of as-cast and extruded Mg-（Ce, Nd）-Zn-Zr alloys

1INTRODUCTION Thebeneficialinfluenceofrareearth(RE)metalsontheambientandelevatedtemperature mechanicalpropertiesofmagnesiumalloyhaslongbeenrecognized[13].Recently,Yttriumisaddedto Magnesiumalloytoimproveitstensilestrength andcreepresistance,andsuchinvestigationsatheat resistantmagnesiumalloyhaveledtothede velopmentofWE43andWE54alloys[4,5].Al thoughsuchalloysexhibitgoodpropertiesupto573Kthroughcastingandextruding,therelativelyhighcostofYttriumrestrictstheapplicationof suchalloys.Otherr…     

镁合金疲劳行为的研究现状及展望

简要介绍了镁合金在疲劳加载条件下的循环应力响应行为、疲劳裂纹萌生与扩展行为以及疲劳断裂的微观特征，分析了镁合金的显微组织、冶金和表面状态等材料内在因素以及环境、温度等外部因素对镁合金的疲劳强度、疲劳寿命、疲劳裂纹扩展速率的影响规律，指出了机械抛光、喷丸处理、表面滚压等表面机械加工方法以及适当的热处理均可有效地提高镁合金的疲劳强度和疲劳寿命.此外，也对镁合金疲劳行为的未来研究方向和发展趋势进行了展望.     

钛基人工骨种植体表面改性研究进展

钛及钛合金以其良好的生物相容性、合适的机械性能和物理特性而被越来越多地应用于骨科移植,表面改性是将钛及其合金应用于骨组织工程最基本的技术．作者从化学处理改性、钛表面生成钙磷陶瓷涂层改性、生物化学方法改性三个方面总结了目前钛基人工骨表面改性技术的研究现状及进展．     

Preliminary Investigation of Copper Joints Soldered with Sn58Bi

In recent years, intensive studies have been carried out to find an alternative for Tin (Sn)-Lead (Pb) solder alloys with increasing demand over lower temperature solder alloys in current electronic packaging industry. High temperature operational solder alloys seem to produce drawback to other components on the printed circuit board (PCB). Low melting temperature Sn58Bi substrate as a potential replacement was investigated in this paper based on the melting properties, wettability, and shear strength. The Sn58Bi was soldered at a temperature below 200 ℃ on the Cu substrate, and the shear strength and contact angle were calculated. A peak temperature (melting temperature, TM) of 144.83 ℃ was identified. Single lap joint method was performed at a strain rate of 0.1 mm/min and an average shear strength of 23.4 MPa was found from three samples. The contact angle (wettability) was calculated to study the solder joint behaviour at reflow temperature of 170 ℃. The contact angle of the Sn58Bi was found to be 32.4 ° and considered to be desired value since the angle is less than 50 °. The low temperature soldering provides a preliminary result to allow further application on the real PCB.     

应变速率对注浆体力学特性影响规律

为研究微震荷载作用下注浆加固体力学特性,以裂隙倾角30°、宽度4 mm的红砂岩裂隙注浆体为研究对象,借助岩石三轴伺服压力机进行变应变速率(10^-5 ~5×10^-3 s^-1)单轴压缩试验;然后从能量耗散、裂纹扩展及破坏形态等3个方面,分析变应变速率对注浆体力学特性的影响规律及机理. 研究表明:随着应变速率的增加,注浆体的峰值强度、弹性模量均随之而增大;且峰值强度与应变速率呈指数函数关系变化;注浆体受应变速率影响的响应分为敏感应变速率阶段和滞缓应变速率阶段,主要差异在于峰值强度变化率和弹性模量变化率;随着应变速率的增大,注浆体的总能量在增大;压密阶段是影响不同应变速率下注浆体力学特性的主要阶段;敏感应变速率阶段和滞缓应变率阶段中的压密阶段主要区别在于积散比大小,积散比进一步决定产生裂纹的多少和分布区域与规律;耗散能密度对注浆体破坏脱落面积以及粒径分布影响较大,耗散能密度越大,碎块越以大块为主(粒径大的比率逐渐增加),滞缓应变率阶段耗散能密度较敏感应变率阶段大,其破碎块体较敏感应变率阶段大. 研究在裂隙注浆加固体的变应变速率影响下力学特性,从能理原理、分形理论角度得到了其影响机理.     

无铅焊锡材料的动态力学性能

利用分离式霍普金森拉压杆技术分别对63Sn37Pb、96.5Sn3.5Ag以及96.5Sn3.0Ag0.5Cu在600、1200以及2200 s-1应变率下的拉伸和压缩动态力学性能进行了测量,得到了不同应变率下的应力应变曲线.结果表明:3种材料均具有明显的应变率效应,其中,96.5Sn3.5Ag对应变率较为敏感;在相同应变率下96.5Sn3.0Ag0.5Cu呈现出最大的屈服应力和抗拉强度.给出了2种无铅焊料抗拉强度、失效点应变与应变率之间的拟合关系.     

Dynamic Mechanical Characteristics and Damage Evolution Model of Granite

By using the technique of the split Hopkinson pressure bar (SHPB),impact tests at different stress wavelengths(0.8-2.0 m) and strain rates (20-120 s-1) were conducted to study the dynamic mechanical properties and damage accumulation evolution law of granite.Test results show that the dynamic compressive strength and strain rate of granite have a significantly exponential correlation;the relationship between peak strain and strain rate is approximately linear,and the increase of wavelengths generally makes the level of peak strain uplift.The multiple-impacts test at a low strain rate indicates that at the same wavelength,the cumulative damage of granite shows an exponential increasing form with the increase of strain rate;when keeping the increase of strain rate constant and increasing the stress wavelength,the damage accumulation effect of granite is intensified and still shows an exponential increasing form;under the effect of multiple impacts,the damage development trend of granite is similar overall,but the increase rate is accelerating.Therefore the damage evolution model was established on the basis of the exponential function while the physical meaning of parameters in the model was determined.The model can reflect the effect of the wave parameters and multiple impacts.The validity of the model and the physical meaning of the parameters were verified by the test,which further offer a reference for correlational research and engineering application for the granite.     

Microstructure,martensitic transformation and shape memory effect of polycrystalline Cu-Al-Mn-Fe alloys

In this study, two Cu-Al-Mn-Fe polycrystalline alloys were prepared, and their microstructure, reversible martensitic transformation, mechanical properties and shape memory effects were investigated. The results show that the reversible martensitic transformation temperatures of the studied alloys are between room temperature and 373 K, which are suitable for practical applications. Two typed martensites of 18R and 2H coexist both in two alloys. The bcc β(FeAl) nanoparticles are Fe-rich, Mnrich and Cu-poor, whereas the martensite is Cu-rich, Fe-poor and Mn-poor. The size of nanoparticles ranges from tens to hundreds of nanometers. Full shape recovery property is displayed in Cu-12.9Al-4.5Mn-2.6Fe alloy all the time while applying different deformation from 5% to 8%. The maximum recoverable strain is up to 4.4% with a recovery rate of 100%.