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.研究结果表明:在300 ℃钎焊90 s后,AuSn/(Ni/AlSi)焊点形成细小的层状(ζ-Au5Sn)+(δ-AuSn)共晶组织和针状的(Ni,Au)3Sn2相.焊点在200 ℃固相老化退火不同时间后,共晶组织明显粗化,焊料/基体界面处形成(Au,Ni)Sn+(Ni,Au)3Sn2复合金属间化合物(IMC)层,且随退火时间延长逐渐增大.退火时间达1 000 h时,在(Ni,Au)3Sn2/Ni界面处产生(Ni,Au)3Sn相.当退火时间小于300 h时,焊点剪切强度随退火时间延长逐渐降低,断裂形式主要是发生在焊料/IMC界面的脆性断裂.退火时间继续延长剪切强度基本不变,断裂主要发生在IMC内部,而且从断裂模型沿晶断裂转变为穿晶断裂. 关键词:AuSn/(Ni/AlSi)焊点;固相老化退火;金属间化合物(IMC);脆性断裂 中图分类号:TG156.21  ......
J. Cent. South Univ. (2017) 24: 708-719 DOI: 10.1007/s11771-017-3472-2 Determination of isolation layer thickness for undersea mine based on differential cubature solution to irregular Mindlin plate... subsea mine of China. Furthermore, thickness optimizations for the protection layers above each stope were conducted based on the maximum principle stress criterion, and the linear relations between......
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J. Cent. South Univ. (2017) 24: 2940-2950 DOI: https://doi.org/10.1007/s11771-017-3708-1 Energy analysis of rock plug thickness in karst tunnels based on non-associated flow rule and nonlinear... tunnel face. Therefore, it is a pivotal issue to determine the reserved thickness of rock plug during the construction of tunnels. The limit analysis principle is employed to analyze the safe thickness......
RCT-β Thickness Gauge Has Been DevelopedH.X.F.摘 要:<正> The RCT-β thickness gauge is a non-contact type instrument used for measuringthickness,which... degree of the attenuation in the intensity of the β-ray corresponds to the thick-ness of the material.The β-ray thickness gauge basing on this principle has been developed,whichis used to measure......
. SMIT Center, Chalmers University of Technology, 412-96 G?teborg, Sweden) 摘 要:研究了Cu/Sn-3.0Ag-0.5Cu/Cu焊点在(150±1)℃时效温度下,0~1 000 h不同时间时效后焊点的拉伸断裂性能以及界面金属间化合物(IMC)的组织形态和成分.结果表明:随着时效时间的延长,焊点拉伸强度降低,拉伸断裂主要发生于Solder/IMC界面或/和IMC/IMC界面,而且断口形貌逐渐由韧窝状断口为主向解理型脆性断口转变.SEM研究发现,时效过程中界面IMC不断长大,增厚并呈针状或块状从Cu/Solder界面向焊点心部生长,时效1 000 h的焊点中IMC分层明显.半焊点结构为Cu/Cu3Sn/Cu6Sn5/Solder,同时,在靠近铜基体的IMC中有Kirkendall空洞存在. 关键词:金属间化合......
Finite element analysis on stresses field of normalized layer thickness within ceramic coating on aluminized steel WU Zhen-qiang(吴振强), XIA Yuan(夏 原), LI Guang(李 光), XU Fang-tao(徐方涛) Institute... dipping aluminum(HDA) and plasma electrolytic oxidation(PEO). A triangle of normalized layer thickness was created for describing thickness ratios of HDA/PEO coatings. Then, the effect of thickness......
J. Cent. South Univ. (2016) 23: 2346-2353 DOI: 10.1007/s11771-016-3293-8 Minimum safe thickness of rock plug in karst tunnel according to upper bound theorem YANG Zi-han(杨子汉), ZHANG Jia-hua(张佳华... ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved......
J. Cent. South Univ. (2019) 26: 955-969 DOI: https://doi.org/10.1007/s11771-019-4063-1 An attribute recognition model for safe thickness assessment between concealed karst cave and tunnel HUANG Xin... model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory. The model can be applied to carrying out risk classification......
:利用SP009A型半自动非金属系制造器,通过铜制单辊快淬工艺制得快速凝固态Sn2.5Ag0.7Cu钎料合金薄带,采用JSM-5610LV 扫描电镜及能谱仪,研究快速凝固态钎料合金的微观形貌及金属间化合物(IMC)特征;通过钎焊接头组织与剪切断口分析,研究IMC对钎焊接头韧性的影响机制.结果表明:快速凝固态钎料合金焊点界面处形成的排列紧密的小尺寸β-Sn能有效抑制界面处IMC Cu6Sn5的长大;在... with SP009A semi-automatic nonmetal series fabricate machine, and the micro-morphology and properties of intermetallic compound (IMC) were studied by JSM-5610LV scanning electronic microscope and energy......