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论述了与其它焊接方法相比,激光焊接微米晶粒钢的优越性.
实验分别在3 kW和6 kW两种不同的CO2激光器上进行.焊接材料为3 mm厚SS400微米晶粒钢.实验研究了不同激光能量输入情况下,焊接接头各区域的硬度、尺寸及组织转变特点.并对能量输入差别较大的不同焊接方法(激光、等离子弧、MAG)焊接微米晶粒钢的焊缝宏观形貌、晶粒度、硬度及冲击韧性进行了对比研究.结果表明:1)激光焊接超细晶粒钢焊缝和热影响区的尺寸比等离子弧和MAG焊接的要窄得多,焊缝晶粒度为后两者的十分之一左右,激光焊接是高质量焊接微米晶粒钢的首选焊接方法;2)激光焊接微米晶粒钢接头没有出现软化区,大能量输入的等离子弧及MAG焊接接头出现了软化区,冲击结果显示激光焊缝比等离子弧焊缝的冲击韧性高出50%以上.(OE14) 相似文献
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激光熔化沉积TC17钛合金光纤激光焊接特性 总被引:1,自引:1,他引:0
利用光纤激光对激光熔化沉积TC17钛合金与锻造TC17钛合金薄板进行了激光热导熔化焊接,利用光学显微镜、扫描电镜、X射线衍射仪和显微硬度计分析了接头的组织结构及显微硬度分布。结果表明,TC17钛合金激光熔化沉积件及锻件薄壁板状试样激光焊接接头凝固组织为沿未熔母材外延定向生长的细小树枝晶组织。锻造钛合金焊缝热影响区(HAZ)大且热影响区β晶粒发生了严重的长大现象,而激光熔化沉积钛合金焊缝热影响区小且热影响区β晶粒尺寸几乎无明显变化,表现出优异的焊接热稳定性。无论锻造钛合金还是激光熔化沉积钛合金,其焊缝区显微硬度高于母材,热影响区显微硬度低于母材。 相似文献
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为了研究纯钛薄板激光对焊接头性能,采用光纤激光器及其配备的机器人组成的焊接系统对其进行了焊接试验,通过测试接头拉伸性能、扩孔率及杯突值,综合评价离焦量对接头性能的影响,并揭示了接头显微组织构成。结果表明,接头拉伸及成形性能均低于母材,离焦量对拉伸性能无直接影响,在一定范围内,接头成形性能随离焦量升高呈现上升趋势,当离焦量为+20mm时,接头拉伸性能及成形性能最佳;焊缝区显微组织为粗大α晶粒+锯齿状α晶粒+少量针状α晶粒,针状α晶粒的存在有利于提高接头的成形性能,热影响区显微组织构成为不规则的粗大α晶粒+锯齿状α晶粒,热影响区晶粒尺寸低于焊缝区晶粒尺寸。该研究对纯钛激光焊接具有一定的理论指导意义。 相似文献
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YG20/45#钢激光焊焊缝组织与界面元素扩散研究 总被引:1,自引:0,他引:1
在无填充、不开坡口条件下,以5 k W光纤激光作为热源,研究激光扫描速度对YG20硬质合金与45#钢的焊缝组织与元素扩散的影响规律。分析了YG20/45#钢焊缝成形、组织及元素扩散。讨论了激光扫描速度对于热胀系数差异较大的异质材料焊接的焊缝成形的影响规律。研究结果表明,当被焊材料厚度为2 mm时,采用激光功率P=1.93 k W、激光扫描速度v=2.40 m/min,离焦量-8 mm时,可以获得冶金结合良好的YG20/45#钢焊接接头;随着焊接热输入的增加,硬质合金/焊缝侧界面的碳化钨晶粒粗化,裂纹倾向增加。主要分布在焊缝和硬质合金侧热影响区,降低焊接接头的性能。线扫描分析结果表明,硬质合金中的W、Co与钢中Fe发生了互相扩散,使整个接头达到了很好的冶金结合。 相似文献
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《中国激光》2016,(3)
为了促进船用高强钢结构激光焊接技术发展,利用光纤激光对8 mm厚的10CrSiNiCu钢板进行了填丝对接焊接。分析了焊接接头的微观组织形貌与硬度、拉伸、弯曲和冲击等力学性能,研究了焊接热输入对接头组织与性能的影响。结果表明,10CrSiNiCu钢激光焊焊缝区组织主要为马氏体+铁素体+贝氏体;热影响区粗晶区组织主要为块状铁素体+粒状贝氏体+马氏体。焊接接头硬度分布不均匀,焊缝区硬度最高,热影响区次之。当焊接线能量从5.00 k J/cm降至3.64 k J/cm时焊缝区硬度从346 HV增加至396 HV。接头拉伸试样均断裂在母材。3倍板厚压头作用下焊接试样可正向弯曲约113°,比母材降低近60°。熔合线和焊缝区的低温(-40℃)冲击功随着焊接热输入的增加而先增加后减小,在E=4.20 k J/cm时熔合线和焊缝区的冲击功最高,分别达到95 J和101 J,冲击试样断口均呈韧性断裂特征。 相似文献
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采用复阻抗分析方法研究了Sb2O3、MnO及Cr2O3掺杂对复合陶瓷ZnO-0.17Ba0.8Sr0.2TiO3(ZnO-0.17BST)晶粒相、晶界相电阻的影响,采用XRD、SEM测量了试样的晶相、微观形貌。结果表明:掺杂并没有改变复合陶瓷的相组成,Sb2O3掺杂,Sb2O3-MnO共掺杂和Sb2O3-MnO-Cr2O3共掺杂的三组试样,其晶粒相电阻随掺杂试剂种类的增多依次减小,晶界相电阻先减小后增加。掺杂氧化物不同,其晶粒、晶界相电阻对复合体系电阻的贡献不同。考虑到晶界相的含量,在掺杂ZnO-0.17BST复合陶瓷电导中,晶粒相起主导作用。 相似文献
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掺Y~(3+)、La~(3+)的(Sr,Ca)TiO_3系多功能陶瓷 总被引:3,自引:0,他引:3
用稀土离子Y(3+)、La(3+)对(Sr,Ca)TiO3掺杂,以Ba-Si-Al玻璃为助熔剂,在1350~1450℃还原性气氛中烧成,获得工艺性能良好、烧结温度较低、晶粒电阻率低(10(-2)Ω·cm)、非线性高(α达10以上)的陶瓷材料。在制备过程中省略了以往用碱金属离子涂覆并进行热扩散的工序。用缺陷化学理论,根据测量的ICTS谱、I-V特性和C-V特性系统研究了Y(3+)、La(3+)掺杂对晶粒半导化、压敏特性和介电特性的影响。热处理过程中,O-的化学吸附是这类陶瓷产生晶界势垒的主要原因。 相似文献
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为了提高警察破案过程中耳纹识别的准确度,克服传统算法针对挤压耳纹形变的高维度干扰,提出了一种挤压状态下耳纹识别的报警方法。在传统算法的基础上,利用计算机视觉耳纹图像标准差和局部均值处理对耳纹图像灰度值进行处理,融合PSA算法与LDA算法,对挤压状态下识别耳纹图形向量进行非线性降维处理,产生具有较强判断能力的挤压状态下耳纹识别分类器,完成高精度误别。仿真结果表明:该算法有效降低了挤压等外界因素对耳纹识别技术的影响,提高了识别的准确度。 相似文献
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准确地评定钢材金相组织晶粒度等级能检测材料劣化情况,保障设备的服役安全。针对传统人工评定钢材金相组织晶粒度等级的方法耗时久且易受人工经验影响,评价结果一致性差且不可重复等问题,提出了一种基于深度学习的钢材金相晶粒度等级评定方法。在U-net模型上添加跳跃连接层并减少下采样次数来提高模型的分割准确率并减少网络参数量,在117张验证集上的像素准确率达93.86%,平均像素准确率(mean pixel accuracy,MPA)达86.89%,网络参数量仅为2.02 M。对晶界预测结果进行数字图像处理并结合截点法进行晶粒度等级评定,在测试图像上评定钢材晶粒度等级平均耗时仅8.3 s/张。与人工评级方法相比,本文方法具有准确性、高效性及可重复性。 相似文献
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利用图像分析软件不仅能定量测量材料的晶粒度,还能得到材料的晶粒尺寸分布图.介绍了统计晶粒尺寸分布和定量测量晶粒度的方法及怎样计算平均晶粒半径和标准差.为研究晶粒尺度对材料性质的影响和材料的理化检测提供准确丰富的依据. 相似文献
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Ann N. Campbell Russell E. Mikawa David B. Knorr 《Journal of Electronic Materials》1993,22(6):589-596
The relationship among the grain structure, texture, and electromigration lifetime of four Al-1% silicon metallizations produced
under similar sputtering conditions was explored. The grain sizes and distributions were similar and the grain structure was
near-bamboo for all metallizations. All metallizations exhibited a near-(111) fiber texture, as determined by the pole figure
technique. Differences in electromigration behavior were noted. Three of the metallizations exhibited a bimodal failure distribution
while the fourth was monomodal and had the longest electromigration lifetime. The electromigration lifetime was directly related
to the strength of the (111) fiber texture in the metallization as anticipated. However, whereas the grain size distribution
has an effect on the electromigration lifetime when metallization lines are several grains wide, the electromigration lifetime
of these near-bamboo metallizations appeared independent of the grain structure. It was also observed that a number of failures
occurred in the 8 μm interconnect supplying the 5 μm wide test lines. This apparently reflects an increased susceptibility
of the wider interconnect lines to electromigration damage. 相似文献
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Some further microstructural characteristics of face-centered cubic polycrystalline metal thin films
We have made detailed observations of gold thin films and commercial aluminum-copper alloy films, using transmission electron
microscopy. All of the films embody a strong <111> fiber texture. We have measured the misorientation distributions for the
grain boundaries in these films, and also determined the “grain boundary character distribution” in terms of the coincident
site lattice model. We show that in spite of their apparent similarity, these films embody significant differences in terms
of these measures. 相似文献
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Yunji L. Corcoran Alexander H. King Nimal de Lanerolle Bonggi Kim 《Journal of Electronic Materials》1990,19(11):1177-1183
A kinetics study of titanium silicide formation is described. The results show that a fine grained precursor layer exist in
between the well developed C-54 silicide layer and the unreacted titanium film. This layer is a mixture of C49-TiSiV2 and unreacted titanium. The fact that no C54-TiSi2 formed directly from the Ti-Si reaction suggests that the nucleation of C49-TiSi2 is easier than that of C54-TiSi2 under our annealing conditions. The silicide layer growth has a non-t1/2 dependence and is much better described by a grain boundary diffusion limited model giving different kinetics. This indicates
that grain boundary diffusion is the major atomic transportation mechanism. The growth rate depends on both the grain boundary
diffusion coefficient and the silicide grain growth rate. 相似文献
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Theory for intermetallic phase growth between cu and liquid Sn-Pb solder based on grain boundary diffusion control 总被引:3,自引:0,他引:3
Kinetics of phase formation during interdiffusion in solid-liquid diffusion couples are influenced by the morphology of the
intermediate compound layer. In some cases, an intermediate compound layer is formed which has very fine grain size. This
condition favors grain boundary diffusion as the predominant mechanism for transport through the layer. In systems where grain
coarsening occurs, the coarsening kinetics will influence the interdiffusion kinetics. In addition, for some solid-liquid
systems, a grain boundary grooving effect is observed which leads to a highly nonuniform layer thickness; the layer is thinner
where the liquid phase penetrates the grain boundaries. As a consequence of the grooving effects, the diffusion path through
the layer is shorter along the grain boundaries. This differs from standard interdiffusion models which assume that the diffusion
distance is equal to the average layer thickness. A model for growth kinetics of an intermediate compound layer is presented
for the case where grain boundary diffusion is the predominant transport mechanism. The model includes the geometric effects
caused by grain boundary grooving. The model predicts layer growth which follows a t1/3 dependence on time t. Experimental data for intermetallic growth between copper and 62Sn-36Pb-2Ag solder exhibit a t1/4 dependence on time t. If experimental data are interpreted in terms of the grain boundary diffusion control model presented
in this paper, the activation energy for grain boundary diffusion is 27 kJ/mole. 相似文献