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对日本交通运输工具中使用较多的析出强化型铝合金A6061板材,在改变温度和变形速度的情况下的应力—应变关系进行了较深入的研究。 相似文献
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The non-linear equations of strings under a concentrated load were derived.The formulae of the linear frequency and the governing equation of the primary resonance were obtained by Galerkin and Multiple-dimensioned method.The reason of the loss of load in practical engineering was addressed.The bifurcation graphics and the relationship graphics of bifurcate point with concentrated load and the span length of the cable were obtained by calculating example.The results show that formula of the linear frequency of the suspended cable is different from that of the string. 相似文献
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为提高Ti6Al4V合金的高温抗氧化性能,以Ni-48%Mo-32%Si混合粉末为原料,采用激光熔覆技术在Ti6Al4V合金表面制备复合涂层,分析涂层物相、组织结构、高温抗氧化性能及抗磨损性能,并讨论相关机理。结果表明:复合涂层中无裂纹,与基体实现了良好的冶金结合;硬质相Ti5Si3、MoSi2和Mo5Si3均匀分布于基体α-Ti、NiTi中。经恒温800 ℃氧化100 h后,复合涂层的氧化膜主要由TiO2、SiO2和NiO组成,结构连续致密,表现出较好的高温抗氧化性能。而Ti6Al4V合金氧化膜主要为疏松TiO2,表面氧化严重;氧化后,复合涂层和基体的单位面积增重分别为1.31和23.38 mg/cm2;复合涂层和基体的摩擦因数分为0.44和0.52、磨损率分别为16.2×10-5和22.6×10-5mm3/Nm,复合涂层的摩擦学性能亦有明显提高。 相似文献
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采用激光熔覆同步送粉法在304不锈钢上制备出自润滑耐磨涂层,熔覆粉末配比为纯Co,Co-2%Ti3 SiC2(质量分数,下同)和Co-8%Ti3 SiC2.借助扫描电子显微镜(SEM),能谱分析仪(EDS)和X射线衍射仪(XRD)对熔覆涂层进行表征,系统地研究304不锈钢与涂层在室温和600℃下的摩擦学性能与磨损机理.结果表明:激光熔覆Co-Ti3 SiC2涂层的平均显微硬度高于基体(240.3HV0.5),N1,N2和N3涂层的硬度分别为285.7HV0.5,356.3HV0.5和463.8HV0.5,涂层主要由连续基体γ-Co固溶体,硬质相Fe2 C,Cr7 C3和TiC,润滑相Ti3 SiC2组成.在室温下,基体和N1,N2,N3涂层的摩擦因数分别为0.56,0.62,0.68和0.42,N1,N2,N3三种涂层的磨损率分别为9.15×10-5,7.81×10-5,4.66×10-5 mm3/(N·m),均明显低于基体(66.42×10-5 mm3/(N·m));在高温下,基体和N1,N2,N3涂层的摩擦因数为0.66,0.54,0.52和0.46,N1,N2,N3三种涂层磨损率分别为37.79×10-5,35.6×10-5,18.83×10-5 mm3/(N·m),均低于基体(41.3×10-5 mm3/(N·m)).在室温和600℃下,涂层具有高于304不锈钢基体的显微硬度,且Co-8%Ti3 SiC2涂层呈现出最好的自润滑耐磨性能. 相似文献
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The element-free method is a new numerical technique presented in recent years.It uses the moving least square(MLS) approximation as its shape function,and it is determined by the basic function and weight function.The weight function is the mainly determining factor,so it greatly affects the accuracy of the computational results.The element-free Galerkin method(EFGM) was applied for the solution to plastic large deformation.The simulation of metal rheological forming was successfully done by programming and its results were visualized by using the plotting and data analyses software Tecplot.Then plastic strain under different stages during rheological forming and the three principal stresses at the last deformation were obtained.The example shows the feasibility of EFGM used for metal rheological forming and provides a new method for numerical simulation of rheological forming of complex parts. 相似文献
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By studying and summarizing the characteristics of wood rheology,the mathematic models of creep and mechano-sorptive creep of wood were analyzed.Rheology behaviors in process,especially drying stress and deformation set were discussed.Application of wood rheology in woodcraft process was elaborated and the research prospects and orientation were forecasted. 相似文献
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Ti_3SiC_2作为一种新型的陶瓷材料,兼具金属和陶瓷的双重性能,同时也由于具有良好的导电导热性、低密度、机械可加工性、优异的抗热震性能、高熔点、高热稳定性、耐高温氧化、耐腐蚀性能,近年来受到了越来越多研究者的关注。首先介绍了Ti_3SiC_2内部晶体学结构,指出其与二元碳化物Ti C有着紧密的晶体学关系,接着详细叙述了各种Ti_3SiC_2制备工艺及其复合材料的研究现状,阐述了化学气相沉积(CVD)、磁控溅射(MS)、脉冲激光沉积(PLD)、自蔓延高温合成(SHS)、热等静压(HIP)、热压烧结(HP)、火花等离子烧结(SPS)等技术在制备Ti_3SiC_2及其复合材料方面的优点和不足。随后重点分析了温度、滑动速度、载荷、添加组分含量、对偶材料种类和润滑环境等因素对Ti_3SiC_2及其复合材料摩擦学性能的影响。最后总结了在Ti_3SiC_2及其复合材料研究中存在的一些问题,并指出进一步提高摩擦磨损性能,添加多元增强相,改进现有技术以及采取新型制备工艺,是未来发展的重要方向。 相似文献