The Fe-rich intermetallic compounds in Al-17Si-2 Fe were modified via Al-Mn-Ti quasicrystal master alloy.The effect of master alloy content on the Fe-rich phase morphology was studied by scanning electron microscope(S...The Fe-rich intermetallic compounds in Al-17Si-2 Fe were modified via Al-Mn-Ti quasicrystal master alloy.The effect of master alloy content on the Fe-rich phase morphology was studied by scanning electron microscope(SEM)and thermodynamic calculation.Results show that the microstructure of the Al-Mn-Ti master alloy consists of binary quasicrystal matrix and ternary AlMnTi secondary phase.The evolutive tendency of Fe-rich intermetallic compounds with content of quasicrystal Al-Mn-Ti master alloy increasing can be described as follows:long needle-shapedβphase for Al-17 Si-2 Fe alloy,long plate-shaped ternaryδphase for 3 wt%master alloy addition,Chinese-script and polyhedralαphases for 4 wt%master alloy addition and finer plate-shaped quaternaryδphase with a phases for 5 wt%master alloy addition.The ultimate tensile strength of the Al-17 Si-2 Fe alloy with4 wt%master alloy addition(a mass ratio of w(Mn)/w(Fe)≈0.7)increases by 23.8%and the friction coefficient decreases from 0.45 to 0.35 compared with those of Mnfree alloy.α-Fe phases have less negative effect on the matrix compared with the long needle-shapedβphase and the plate-shapedδphase.展开更多
The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and diff...The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.展开更多
以不同脱氧方式熔炼的海洋工程用钢为研究对象,利用SEM、EDS及Image-Pro Plus 6.0软件对钢中夹杂物形貌、组成及尺寸分布等进行表征,通过3.5%NaCl溶液中阳极极化及腐蚀实验对钢中夹杂物诱发点蚀的行为进行探究。结果表明,与Al-Mg脱氧钢...以不同脱氧方式熔炼的海洋工程用钢为研究对象,利用SEM、EDS及Image-Pro Plus 6.0软件对钢中夹杂物形貌、组成及尺寸分布等进行表征,通过3.5%NaCl溶液中阳极极化及腐蚀实验对钢中夹杂物诱发点蚀的行为进行探究。结果表明,与Al-Mg脱氧钢相比,Ti-Mg脱氧钢中形成了含有TiO_x的复合氧化物,夹杂数量更多且平均尺寸更小(小于1μm),有利于MnS的异质形核析出及弥散分布;低腐蚀活性的含TiOx复合氧化物及高度分散、异质局部析出MnS夹杂具有较低的点蚀敏感性及自腐蚀催化作用,降低了点蚀的诱发及扩展,有效提高了钢的抗点蚀性能。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51201071)the National Natural Science Foundation of Jiangsu Provence(BK20161270)Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents(2018)。
文摘The Fe-rich intermetallic compounds in Al-17Si-2 Fe were modified via Al-Mn-Ti quasicrystal master alloy.The effect of master alloy content on the Fe-rich phase morphology was studied by scanning electron microscope(SEM)and thermodynamic calculation.Results show that the microstructure of the Al-Mn-Ti master alloy consists of binary quasicrystal matrix and ternary AlMnTi secondary phase.The evolutive tendency of Fe-rich intermetallic compounds with content of quasicrystal Al-Mn-Ti master alloy increasing can be described as follows:long needle-shapedβphase for Al-17 Si-2 Fe alloy,long plate-shaped ternaryδphase for 3 wt%master alloy addition,Chinese-script and polyhedralαphases for 4 wt%master alloy addition and finer plate-shaped quaternaryδphase with a phases for 5 wt%master alloy addition.The ultimate tensile strength of the Al-17 Si-2 Fe alloy with4 wt%master alloy addition(a mass ratio of w(Mn)/w(Fe)≈0.7)increases by 23.8%and the friction coefficient decreases from 0.45 to 0.35 compared with those of Mnfree alloy.α-Fe phases have less negative effect on the matrix compared with the long needle-shapedβphase and the plate-shapedδphase.
文摘The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDX）, and differential scanning calorimeter （DSC） methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is （510 °C, 18 h）, which agrees well with the results of homogenization kinetic analysis.
文摘以不同脱氧方式熔炼的海洋工程用钢为研究对象,利用SEM、EDS及Image-Pro Plus 6.0软件对钢中夹杂物形貌、组成及尺寸分布等进行表征,通过3.5%NaCl溶液中阳极极化及腐蚀实验对钢中夹杂物诱发点蚀的行为进行探究。结果表明,与Al-Mg脱氧钢相比,Ti-Mg脱氧钢中形成了含有TiO_x的复合氧化物,夹杂数量更多且平均尺寸更小(小于1μm),有利于MnS的异质形核析出及弥散分布;低腐蚀活性的含TiOx复合氧化物及高度分散、异质局部析出MnS夹杂具有较低的点蚀敏感性及自腐蚀催化作用,降低了点蚀的诱发及扩展,有效提高了钢的抗点蚀性能。
