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激光电弧热源复合模式对301L不锈钢焊接接头性能的弱化机制
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作者 杨涛 汪远 +3 位作者 庄园 杨瑞欣 曾俊谚 李桓玉 《焊接学报》 EI CAS CSCD 北大核心 2022年第9期56-61,I0006,共7页
激光电弧复合焊在传统的激光填丝焊基础上加入了电弧形成复合热源,导致电弧区产生热量积累,造成焊缝晶粒粗大,并弱化了焊接接头的强度和断后伸长率,促使焊接结构的服役安全性能大幅降低.通过建立三维熔池温度模型及力学性能分析阐明了... 激光电弧复合焊在传统的激光填丝焊基础上加入了电弧形成复合热源,导致电弧区产生热量积累,造成焊缝晶粒粗大,并弱化了焊接接头的强度和断后伸长率,促使焊接结构的服役安全性能大幅降低.通过建立三维熔池温度模型及力学性能分析阐明了激光与电弧协同热作用对焊接接头强度和断后伸长率的影响规律.结合焊缝的晶粒尺寸、晶界取向差分布、织构强度从微观晶体学角度揭示了焊接接头强度和断后伸长率的弱化机制.结果表明,电弧介入促使复合热源产生热积累,降低熔池温度梯度,强化了晶粒的择优取向生长及织构强度,导致接头各向异性,从而使焊接接头的断后伸长率降低2%.较低的温度梯度会延长熔池冷却时间,促使晶粒长大和大角度晶界减少,不利于阻碍位错滑移,导致焊接接头平均屈服强度降低35 MPa,极限抗拉强度降低66 MPa.并且随着焊接电流的升高,熔池高温停留时间延长,接头晶粒及织构强度增大,接头强度和断后伸长率继续降低. 展开更多
关键词 301L不锈钢 激光-电弧复合焊接 三维热源模型 微观晶体学
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Enhancement effect of phase-conjugate waves of third order nonlinear medium in the Bragg microcavity 被引量:1
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作者 JIANG Mei-ping CHEN Guang +3 位作者 SHEN Xiao-ming GHEN Xian-feng NI Chong-wen SHI Du-fang 《Optoelectronics Letters》 EI 2006年第1期78-81,共4页
The enhancement effect of the phase-conjugate wave produced by a third order nonlinear optical medium in a (AB)^N (D)^2 (BA)^N Bragg microcavity made of one-dimensional photonic crystals is studied. The gain fac... The enhancement effect of the phase-conjugate wave produced by a third order nonlinear optical medium in a (AB)^N (D)^2 (BA)^N Bragg microcavity made of one-dimensional photonic crystals is studied. The gain factor of the phase-conjugate wave is derived when the resonance condition is satisfied by the incident optical wave and the Bragg microcavity mode. Because of stronger resonance enhancement to incident pump beam given by the Bragg microcavity, the enhancement effect of the phase-conjugate wave produced by a third order nonlinear optical medium inside Bragg microcavity is more outstanding than that caused by the naked third order nonlinear optical medium. The theoretical analysis and the numerical calculation show the Bragg microcavity with larger number N of periods is identical with a Fabry-Perot cavity when the resonance condition is satisfied by the incident optical wave and the Bragg microcavity mode. 展开更多
关键词 非线性光媒介 相位共轭波 微观空穴 晶体光学
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Formation kinetics and transition mechanism of CaO·SiO2 in low-calcium system during high-temperature sintering 被引量:2
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作者 PAN Xiao-lin CUI Wei-xue +1 位作者 ZHANG Can YU Hai-yan 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第11期3269-3277,共9页
The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio o... The crystal structure,formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD,FT-IR,Raman and SEM-EDS methods.When the molar ratio of CaCO3 to SiO2 is 1.0,β-2CaO·SiO2 forms firstly during the heating process,and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2.3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process.Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2,resulting in the sintered products a small blue shift and broadening in Raman spectra.The content of CS can reach 97.4%when sintered at 1400℃ for 1 h.The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model,and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×10^14 s^−1 respectively. 展开更多
关键词 calcium silicate compounds formation kinetics crystal structure MICROSTRUCTURE sinter process
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