（九）八音盒机芯—悬臂梁振动音乐的艺术王国

（九）八音盒机芯──悬臂梁振动音乐的艺术王国蒋本威，庄表中（浙江大学）悬臂梁的第一阶固有振动频率计算公式为应用这个公式选用长度ｌ相同，截面积Ａ和惯性矩Ｉ不同的悬臂梁多根，制成如图１所示的频率测量盒，若要测量振动物体的频率，只要将此仪器放置在上面，应用...     

铝在醚类电解质中的电沉积

本文综合了近期有机试剂中电沉积铝的有关文献，主要介绍了铝在ＡｌＣｌ３与乙醚、四氢呋喃（ＴＨＦ）、１－甲基－３乙基咪唑氯化物（ＭＥＩＣ）、Ｎ－（ｎ－丁基）吡啶氯化物（ＢＰＣ）等满替代的翁盐等组成的电解质中，电沉积的电极过程，以及在ＭＥＩＣ和ＢＰＣ中得到的铝层组织和结构的研究成果，并举例了沉积铝层的应用。     

ZG 1Mn19Ni3Al 铸焊结构低温性能研究

通过化学成分设计和金相组织设计，开发了一种适用于与１６Ｍｎ钢组成铸焊结构的新铸钢ＺＧ１Ｍｎ１９Ｎｉ３Ａｌ。研究了这两种材料组成的焊板在常温、低温（－１９６℃）下的力学性能和冲击断口形貌。试验结果表明，夹杂物和焊接线能量对其低温冲击韧性有着显著的影响。具有γ＋ε双相组织的ＺＧ１Ｍｎ１９Ｎｉ３Ａｌ钢用于低温（－１９６℃）铸焊结构中时要注意钢水精炼和采用适当的焊接线能量     

X射线影像存储材料BaF_xCl_（2－x）Eu~（2＋）的制备及其热释发光和

本文采用了不同温度下两次烧结的新方法，制备了系列Ｘ射线影象存储材料ＢａＦ＿ｘＣｌ＿（２－ｘ）：Ｅｕ￣（２＋）（ｘ＝０．９０，０．９５，１．００，１．０５，１．１０１．１５）。通过改变Ｆ／Ｃｌ比值，研究了在Ｘ射线辐照后ＢａＦ＿ｘＣｌ＿（２－ｘ）：Ｅｕ￣（２＋）的热释发光性质，给出了热释发光峰的温度与缺陷种类的关系。最后，我们研究了ＢａＦ＿ｘＣｌ＿（２－ｘ）：Ｅｕ￣（２＋）的光激励发光性质，给出了Ｆ／Ｃｌ比值与光激励发光强度的关系。     

C,Al,Ti对钢焊接热影响区韧性的影响

微量Ａｌ，Ｔｉ对７９０ＭＰａ级钢焊接ＨＡＺ的韧性有重要的影响。加入Ａｌ后，在５ＫＪ／ｍｍ的焊接线能量下，热模拟试样的ＡＫＶ（－２０℃）与ＡＫＶ（－４０℃）分别为１０４Ｊ与２０Ｊ。与不加Ａｌ的钢相比，分别提高了４．９倍和１．６倍。Ａｌ与Ｔｉ同时加入则ＡＫＶ（－２０℃）与ＡＫＶ（－４０℃）分别为１５１Ｊ和３８Ｊ。如果把母材中的含Ｃ量降低到０．０４％，ＨＡＺ的低温韧性得到更大的改善，本文也探讨了ＡＩＮ，     

高活性催化剂制备乙烯共聚产物的结构与性能：（I）？…

新型高活性催化剂ＴｉＣｌ４、Ｔｉ（ＯＢｕ）４／ＭｇＣｌ２、ＳｉＯ２、ＺｎＣｌ２／醇／ＡｌＲ３体系催化乙烯气相齐聚和共聚合,制得了一系列线性低密度塑性体和极低密度弹性全。用ＤＳＣ、ＦＴ－ＩＲ研究了它们的支化结构、结晶度、结晶与熔融行为。结果表明新型高活性催化剂具有和齐聚性能相关的很好的催化乙烯与１－丁烯共聚合的性能;当共聚单体中１－丁烯含量由７％（体积,不同）增加到２６％,产物的支化度（乙基数／１０     

NiAl（Fe）合金组织和拉伸性能的研究

采用光学显微镜、扫描电镜（ＳＥＭ）、透射电镜（ＴＥＭ）、电子探针（ＥＰＭＡ）、Ｘ射线（ＸＲＤ）和选区电子衍射分析（ＳＡＥＤ）研究了ＮｉＡｌ（Ｆｅ）合金的显微组织及拉伸性能。结果表明，铸态ＮｉＡｌ（Ｆｅ）合金经均匀化退火后的组织由β及β＋γ＇相组成。韧性相γ＇相能阻止裂纹扩展，有利于改善合金的室温塑性。比较发现，Ｎｉ５０Ａｌ２０Ｆｅ３０合金具有最佳的室温塑性，其拉伸断口由β相的解理断口和β＋γ＇相的     

MlβMm1—β（NiCoMnTi）5贮氢合金的电化学性能和Rietveld分析（2）Riet …

在ＡＢ５型混合稀土－镍系贮氢多元合金的研究中，为设计高性能价廉的ＡＢ５型贮氢电极合金，人们对其Ｂ侧多元合金化和Ａ（＝ＲＥ）侧稀奎组元分别进行了系统地研究。本工作通过对ＲＥ（ＮｉＣｏＭｎＴｉ）５合金中称土组元（ＲＥ＝ＭｌβＭｎ１－β）进行组合优化研究，主要还是依赖于市售的混合稀土金属（Ｍｌ和Ｍｍ）原材料，利用不同种类的混合稀土中Ｌａ，Ｃｅ，Ｎｄ，Ｐｒ组中相应变化，来调整其稀土成分。结果表明：Ｍｌ：Ｍ     

耐1300℃新型Ni-Fe-Cr-Al基高温合金抗氧化机理研究

对新型高温合金（３ＹＣ５２）的抗氧化机理进行了系统研究。结果表明，研制合金（３ＹＣ５２）具有的优异抗氧化性能在于高温下合金表面能形成致密保护层。扫描电镜（ＳＥＭ）、电子探针显微分析（ＥＰＭＡ）和Ｘ射线衍射分析（ＸＲＤ）分析表明，１１００℃，合金氧化层的内层为Ｃｒ２Ｏ３，外层为Ａｌ２Ｏ３；１３００℃，合金氧化层为单一的Ａｌ２Ｏ３。差热分析（ＤＴＡ）研究表明（Ａｌ，Ｃｒ）２Ｏ３和α－Ａｌ２Ｏ３的形成分别在１０６０℃和１３５６℃达到最大值。当温度大于１１５０℃时，Ｃｒ２Ｏ３易剥落，因此随着时间的延长，最终留下致密的α－Ａｌ２Ｏ３保护层。     

C、Al、Ti对钢焊接热影响区韧性的影响

微量Ａｌ、Ｔｉ对７９０ＭＰａ级钢焊接ＨＡＺ的韧性有重大的影响，加入Ａｌ后，在５ＫＪ／ｍｍ的焊接线能量下，热模拟试样的ＡＫＶ（－２０℃）与ＡＫＶ（－４０℃）分别为１０４Ｊ与２０Ｊ与不加Ａｌ的钢相比，分别提高了４．９倍和１．６倍．Ａｌ与Ｔｉ同时加入则ＡＫＶ（－２０℃）与ＡＫＶ（－４Ｏ℃）分别为１５１Ｊ和３８Ｊ．如果把母材中的含Ｃ量降低到０．０４％，ＨＡＺ的低温韧性得到更大的改善．本文也探讨了ＡＩＮ、ＴｉＮ在焊接热循环过程中的溶解与析出行为．     

Analysis of Discontinuous Bead Formation by PTAW Process

This research investigates the effects of input parameters on discontinuities in bead formation during material deposition by the plasma transferred arc welding (PTAW) process. Experiments based on L27 orthogonal array have been carried out by deposition of stainless steel powder (SS304 L) on stainless steel plate (SS316). Three types of depositions have been observed, namely continuous, partially continuous and discontinuous deposition. A process map has been developed, based upon powder and energy deposition per length, where the above-mentioned three types of depositions are distributed. The discontinuities in the deposition can be overcome by increasing the energy deposition per length or by reducing the powder deposition per length.     

An Experimental Investigation and Analysis of PTAW Process

Experiments are conducted to deposit SS304 L powders on SS316 plates by plasma transfer arc welding process with varying four input process parameters, namely scanning speed, powder feed rate, stand-off distance, and current. The effects of these four input process parameters on deposition geometry, dilution, and bead continuity are investigated in this study. Attempts have been made to explain the experimental results with only two compound parameters, “energy deposition per length” and “powder deposition per length” instead of four independent input process parameters. It is observed that the variation of dilution is very little when the scanning speed increases from 100 to 600 mm/min and other process parameters remain constant. When the powder feed rate increases and other parameters remain constant, initially the dilution decreases rapidly and attains a minimum value which do not change further with increase in powder feed rate. It is also observed that the dilution remains almost constant around 6–9% as the stand-off distance changes from 7 to 11 mm and other process parameters remain constant. The formation of nonuniform bead is found to be due to insufficient energy deposition per length per mass of supplied powder.     

三维自由弯曲技术及变形区长度优化数值模拟研究

目的 开展自由弯曲变形区长度优化研究,获得外径为15 mm、壁厚为2 mm的6061-T6铝合金管材的最优A值。方法 从三维自由弯曲成形技术的基本原理及控制程序入手,基于有限元分析方法,利用ABAQUS仿真软件对管材三维自由弯曲成形过程进行数值模拟,研究成形过程中管材弯曲变形区的受力过程变化,分析变形区长度(A)对弯曲成形结果的影响规律。基于最优的变形区长度,对制冷系统管路中的6061-T6铝合金复杂空间弯曲构件进行仿真模拟及实际成形试验。结果 试验成形构件尺寸与模拟成形构件尺寸相近且均接近设计尺寸,试验成形构件最大壁厚减薄率不超过9%,最大截面畸变率不超过5%,具有较好的成形质量。结论 目标构件的有限元模拟及成形试验验证了变形区长度优化结果的准确性。     

Optimization of A-TIG process parameters using response surface methodology

In the present work, the influence of process parameters such as welding current (I), welding speed (S), and flux coating density (F) on different aspects of weld bead geometry for example depth of penetration (DOP), bead width (BW), depth to width ratio (D/W), and weld fusion zone area (WA) were investigated by using the central composite design (CCD). 9–12% Cr ferritic stainless steel (FSS) plates were welded using A-TIG welding. It was observed that all input variables have a direct influence on the DOP, BW, and D/W. However, flux coating density has no significant effect on WA. Mathematical models were generated from the obtained responses to predict the weld bead geometry. An optimized DOP, BW, D/W, and WA of 6.95?mm, 8.76?mm, 0.80, and 41.99?mm², respectively, were predicted at the welding current of 213.78 A, the welding speed of 96.22?mm/min, and the flux coating density of 1.99?mg/cm². Conformity test was done to check the practicability of the developed models. The conformity test results were in good agreement with the predicted values. Arc constriction and reversal in Marangoni convection were considered as major mechanisms for the deep and narrow weld bead during A-TIG welding.     

Experimental and numerical assessment of mechanical properties of welded tubes for hydroforming

The identification of welded tubes properties considering the weld bead and Heat Affected Zone (HAZ) is important for reliable and accurate finite element simulation of tubular plastic forming processes such as tube hydroforming and rotary draw bending processes. Therefore, a simplified method is proposed to extract the weld bead and HAZ properties. Full size standard tensile specimens cut from the welded tube and comprising the weld parallel to the load direction are extended to failure. Mechanical properties obtained from uniaxial tensile test are correlated with the microhardness data measured across the welded specimen and by using the rule of mixtures; the constitutive model parameters of weld bead and HAZ regions are identified. Accuracy of the proposed method is assessed by comparing finite element simulation predictions to experimental measurements obtained from two mechanical tests: the first one is the uniaxial tensile test performed on specimens comprising the weld line perpendicular to the loading direction and the second test is the free bulge hydroforming test achieved on seamed tubular samples. This investigation has shown that the presented method is practical in use and sufficiently accurate to extract the weld metal properties of seamed tubes.     

Experimental investigation on the effects of process parameters of GMAW and transient thermal analysis of AISI321 steel

Gas metal arc welding (GMAW) develops an arc by controlling the metal from the wire rod and the input process parameters. The deposited metal forms a weld bead and themechanical properties depend upon the quality of the weld bead. Proper control of the process parameters which affect the bead geometry, the microstructures of the weldments and the mechanical properties like hardness, is necessary. This experimental study aims at developing mathematical models for bead height (HB), bead width (WB) and bead penetration (PB) and investigating the effects of four process parameters
viz: welding voltage, welding speed, wire feed rate and gas flow rate on bead geometry, hardness and microstructure of AISI321 steel with 10 mm thickness. The transient thermal analysis shows temperature and residual stress distributions at different conduction and convection conditions.     

焊缝性能影响因素的研究进展

埋弧焊和氩弧焊的焊缝合金元素及其含量、热输入、晶粒长大、预热温度、冷却速度和峰值温度对焊缝组织与力学性能均有一定的影响。总结了国内外对焊缝组织和力学性能的各种影响因素的相关研究,研究结果表明合金元素(如Mn、Cr、Ni、Mo等)能明显提高焊缝力学性能,每种元素都有合适的添加范围;焊缝接头强度和韧性以及伸长率随热输入的增大而减小;冷却速度的范围是8～12s。通过控制添加合金元素可以有效提高焊缝力学性能并改善焊缝组织,控制合理的热输入范围和冷却速度可提高焊缝的韧性。     

Economic and economic-statistical designs of the side sensitive group runs chart with auxiliary information

This article studies the economic and economic-statistical designs of the auxiliary information (AI) based side sensitive group runs (SSGR-AI) chart. The regression estimator that consists of information not only from the primary variable but also from the auxiliary variable is integrated into the control charting statistic. Optimal designs of the SSGR-AI chart, for the minimization of the expected cost function with and without statistical constraints, are developed based on (i) average run length (ARL) and (ii) expected average run length (EARL). Furthermore, sensitivity analyses are conducted, that is, the impact of various input parameters on the optimal parameters and costs for different values of correlation coefficients (ρ) between the primary and auxiliary variables are investigated. In addition, the effects of incorrect specification of the size of the shift on the optimal cost of the SSGR-AI chart are studied. The comparative study reveals that the SSGR-AI chart is superior to the exponentially weighted moving average-AI (EWMA-AI) and synthetic-AI (Syn-AI) charts, for both designs, by giving the smallest costs.     

Optimization of laser welding process parameters for super austenitic stainless steel using artificial neural networks and genetic algorithm

The laser welding input parameters play a very significant role in determining the quality of a weld joint. The quality of the joint can be defined in terms of properties such as weld bead geometry, mechanical properties and distortion. In particular mechanical properties should be controlled to obtain good welded joints. In this study, the weld bead geometry such as depth of penetration (DP), bead width (BW) and tensile strength (TS) of the laser welded butt joints made of AISI 904L super austenitic stainless steel are investigated. Full factorial design is used to carry out the experimental design. Artificial neural networks (ANNs) program was developed in MatLab software to establish the relationship between the laser welding input parameters like beam power, travel speed and focal position and the three responses DP, BW and TS in three different shielding gases (argon, helium and nitrogen). The established models are used for optimizing the process parameters using genetic algorithm (GA). Optimum solutions for the three different gases and their respective responses are obtained. Confirmation experiment has also been conducted to validate the optimized parameters obtained from GA.     

Mode II fracture testing of composites: a new look at an old problem

A number of technical issues have slowed the progress towards an agreed mode II test protocol for composite laminates and perhaps the most important of these has concerned the difficulty in measuring crack length during the test. In this paper, we extend a previous analysis which was developed for mode I delamination cases where significant bridging and micro-cracking occurred. The approach utilises an effective crack length and if successful, may eliminate the need to measure this parameter experimentally. To accommodate the new approach, an existing test protocol based on the end-loaded split (ELS) method has been revised and some data measured using the scheme is presented. This includes some initial results measured in a round-robin activity co-ordinated by a technical committee of the European Structural Integrity Society (ESIS). A number of materials are examined with a view to determining the utility of the ‘crack length independent’ approach.