The Recovery of Elastic Properties at 35 °C in TRIP 700 Steel Following Deformation

The influence of plastic deformation on the elastic properties that determine the magnitude of springback following forming was investigated using dynamic modulus analysis. For this study, the elastic modulus of TRIP 700 steel was measured continuously at 35 °C and a loading frequency of 1.0 Hz for 1000 min following deformation by cold rolling to varying levels up to 27%. The elastic modulus increased at an exponentially decaying rate during these experiments and with a magnitude that increased with pre-strain. These observations are consistent with the hypothesis that deformation creates microstructural defects that contribute compliance when the stress state changes and that these defects are removed by annealing at this low temperature. This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati, OH, October 15-19, 2006.     

EFFECTS OF TEMPERING TEMPERATURE AND TIME ON SHEAR MODULUS OF Fe-Mn BASED ALLOYS

Effects of the tempering temperature and time on the shear modulus of Fe-Mn based alloyshave been studied.The results show that(ΔG/G)-Tcurves of tempered alloys containingCr and Ti have two extreme values—maximum and minimum,and that the curves of tem-pered alloys containing Cr,Ni,W and C only have a maximum value.This is the reason thatNi,W and C decrease the transformation point T_N of the antiferromagnetism.The ΔG_λ ef-feet increases gradually with the rise of tempering temperature or with the increase of tem-pering time.     

冒口尺寸网络图确定法

以圆柱和腰圆形冒口为例，提出了坐标曲线网络图方法，根据已知的冒口模数，由坐标曲线网络图即可确定任一比例的冒口尺寸。     

单晶硅的纳米硬度测试分析

介绍了测量硬度的几种方法,分析了纳米压痕硬度测量的基本原理。用美国原位纳米力学测试系统中的TriboIndenter对单晶硅进行了试验研究。试验结果表明,由于尺寸效应纳米硬度值随着载荷的增大而逐渐减小,纳米级的压痕试验得到的单晶硅的硬度值要高于其他传统方法测得的宏观硬度值。     

压入深度与膜厚对薄膜与基体复合硬度及弹性模量的影响

根据高华建的复合弹性模量模型，提出了用一个测点的载荷-位移曲线计算整个压入深度内薄膜和基体复合硬度分布的方法，探讨了压入深度与膜厚对硬度与弹性模量测量值的影响，指出可由膜-基复合性能反推膜本身的性能。     

植入用Ti-Nb合金弹性模量及力学性能与显微组织的研究

通过配制5种成分的Ti—Nb合金，研究了Nb对Ti—Nb合金弹性模量及力学性能与显微组织的影响。结果表明：Ti—Nb合金组织中具有β相、α相、α”相等，随Nb含量不同，各相外貌及数量也各不相同；Ti—Nb合金具有较低的弹性模量，较好的塑性，更适合生物体植入。     

超高压溢流阀静动态特性的研究

本文介绍了超高压技术的一些基本特点，对超高溢流阀的静动态特性进行了详细的理论分析与实验研究，阐明了在超高压领域中对单极直动溢流阀分析时与一般压力下的不同点和应注意，并进行了实验论证。     

回火处理对Fe-Mn基合金剪切模量的影响SCIEI

研究了回火温度和时间对两种成分Fe-Mn基合金剪切模量的影响。结果指出,附加Cr,Ti的合金在回火状态下ΔG G-T曲线有极小和极大两个极值,而附加Cr,Ni,W,C的合金只呈现极大值特征。这是由于Ni,W,C降低反铁磁转变点T_N造成的, 随着回火温度升高或回火时间增加,ΔG_λ效应逐渐增加。     

利用硬度计进行弹性模量测试的研究

弹性模量是材料性能的一项重要参数。采用Oliver-Pharr方法计算弹性模量容易受接触深度及初始卸载斜率的影响,尤其是材料呈现堆积状态时。采用量纲分析及有限元仿真,建立材料的弹性模量与压痕参数的解析表达式。数值反演和试验结果表明:提出的方法能获得较高精度的弹性模量,实现了弹性模量的高效测量,降低了试验成本。     

三维铸造工艺CAD系统的开发

在三维模型上，采用离散法计算铸件的模数和重量，从而计算浇冒口系统和冷铁，最后输出工艺卡和铸造工艺图，供设计人员参考和使用．由于铸造工艺ＣＡＤ系统的所有计算功能都是自身的．因而可以很容易地移植到其它系统上。     

Measurements of local elastic moduli by amplitude and phase acoustic microscope

A new method is suggested for the nondestructive measurement of elastic moduli in a localized area, 100–400 μm in diameter, by the complex V(z) curve using an amplitude and phase acoustic microscope. The inverse Fourier transform of the complex V(z) curve contains the reflectance function of a liquid-specimen interface. Therefore, the longitudinal, transverse and Rayleigh wave velocities for the specimen are simultaneously obtained by the inversion of the complex V(z) curve. The elastic moduli for glass obtained from wave velocities by acoustic microscope agree fairly well with those by other methods. The present method is applied to aluminium alloy, and it is shown that this method is useful in measuring the microscopic characteristics in inhomogeneous materials.     

弛豫铁电体Pb(Mg1/3Nb2/3)O3-PbTiO3的相变

测量了(1-x％)镁铌酸铅-x％钛酸铅(1≤X≤11)(简称PMNTx)陶瓷样品的介电常数、内耗和Young’s模量．观测到在Tm温度附近，即在介电常数达到最大值时，出现一个内耗峰，并且模量发生软化．这反映了极化纳米微畴的弛豫．对于PMNTx(5≤x≤11)的样品，在Tm温度以下的某个温度出现附加的内耗峰和Young’s模量的异常，表明样品中发生了自发的弛豫铁电到铁电(简称R-F)的相变，对R-F相变的机制进行了讨论．     

梁三点弯曲法测量薄膜弹性模量

用电刷技术在不锈钢基体一侧表面上刷镀了Cu膜，用电镀技术在不锈钢基体一侧表面或双侧表面上制备Ni膜。用梁三点弯曲法在自制的设备上测量不锈钢基体以及不锈钢基体上不同厚度Cu膜和Ni膜的弹性模量E。研究表明：在测量的膜厚范围内(7μm-15μm)，Cu膜和Ni膜的弹性模量E不随膜厚变化，并且接近各自块材的弹性模量。     

含孔隙多相纳米晶体陶瓷的力学性能计算模型

提出一个晶粒与晶界的混和模型，用于计算单相纳米晶体陶瓷的弹性模量，进而结合Budiansky等人的自洽模型计算了含孔隙多相纳米晶体陶瓷的弹性模量。在此基础上，将正割模量替代弹性模量，在等应变假设的前提下，将提出的能计算含孔隙多相纳米晶体陶瓷弹性模量的模型拓展成能描述该类材料在小塑性变形条件下的应力-应变关系的模型，并且确定σ0．2为含孔隙多相纳米晶体陶瓷的屈服强度。大量计算结果与试验数据的对比表明，所提出的模型能较好地反映晶粒尺寸与孔隙率对纳米晶体陶瓷弹性模量与屈服强度的影响。     

Tensile testing as a method for determining the Young''s modulus of thin hard coatings

The present paper describes and evaluates a tensile testing method for determination of the Young's modulus of thin hard coatings. When applied to PVD TiN and NbN coatings on stainless steel foils, the elastic modulus obtained through force—strain plots ranged between 380 and 425 GPa for TiN coatings, and was 350 GPa for the single NbN coating tested. It is concluded that the method is easy to perform and allows reliable determination of the Young's modulus of thin hard coatings, and that it can be applied to almost any kind of coating on a wide range of substrate materials.     

Ultrasonic and hardness measurements for ultrahigh pressure prepared WB ceramics

The Vickers hardness of pressure synthesized WB compacts was measured using a diamond indentation method. Under the applied load of 4.9 N, our test gave a maximum Vickers hardness of 30.1 GPa for WB compacts. The hardness of WC-8 wt.% Co composites was also measured under the same load for comparison, which was found to be much lower than that of WB. The Young's modulus, bulk modulus, and shear modulus of WB and WC-8 wt.% Co were further investigated by ultrasonic measurements. The results suggest that WB might be a promising hard alloy material for industrial applications.     

基于原子力显微镜的薄膜原位压痕力学性能研究

基于原子力显微镜(AFM)和扫描电子显微镜(SEM)建立了一套原位纳米压痕测试系统。该系统可以实现控制带有金刚石(Cube corner)压头的AFM微悬臂梁对样品进行压入实验,并得到载荷-位移曲线,同时可以对压痕过程进行原位SEM实时观察。发展了一种基于AFM微悬臂梁加载和原位SEM压痕图像分析的力学性能测试方法,通过测量压入最大载荷和原位SEM测量压痕残余面积得到塑性薄膜的硬度和弹性模量。利用此方法对磁控溅射硅衬底上纳米晶银薄膜进行了压痕实验,并与Nanoindenter G200型纳米压痕仪实验进行对比研究。结果表明,原位AFM压痕方法具有高的载荷和位移分辨率,可以实现纳牛至微牛级的压痕实验,通过测量压痕面积得到塑性薄膜的硬度值,减小了使用Oliver-pharr方法中软膜硬基底上凸起(Pile-up)效应的影响,计算结果也具有好的测试精度和可靠性。     

热处理对Tb—Dy—Fe合金声速和弹性模量的影响

本文研究了＜１１２＞轴向取向Ｔｂ０３１Ｄｙ０６９（Ｆｅ１９５Ｍ００５）１９５（Ｍ＝Ｍｎ,Ａｌ等）合金的声速和弹性模量与外加磁场的关系。随着磁场强度的增加,弹性模量和声速逐渐降低,在１０ｋＡ／ｍ时达到最小,随后逐渐增加。在９５０～１０８０℃热处理３ｈ,在相同磁场下材料的声速和弹性模量达到最低值。     

铣齿加工大模数大型齿轮的方法

针对大模数大型齿轮加工存在的问题,提出采用粗加工→半精加工→精加工的加工工艺方案;并将车工序和铣齿工序、热处理与机加工穿插进行。设计了粗加工铣刀和精加工铣刀,按固定弦齿厚进行检测,保证了加工质量。     

灰铸铁的固有振动特性

灰铸铁件作为振动系统，其刚度的材质成分--弹性模量值较低，阻尼比大；在低阶振型时，测得的固有频率较小。在低的结构刚度值条件下，其高阶振固有频率值不高；结构刚度对其影响较小。在高的结构刚度值条件下，其第一高阶振型为跳跃式，有较大的固有频率值，振幅比也大。