Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al...Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable.展开更多
In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, ...In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, sca^lning electron microscopy, mid energy diffraction spectroscopy. The results reveal that the c^-A1 phases were nearly spherical mid 40 gin in size and that the eutectic Si phases became round in the composite when the Sr content reached 0.2wt%. The A13Ti paxticles were distributed uniformly at the grain boundary. The results of the corrosion examination reveal that the A13Ti/ADC12 composite exhibited a minimum corrosion rate of 0.081 g.m 2,hl for an Sr content of 0.2wt%, which is two thirds of that of umnodified composite （0.134 g.m4.h 1）. This improved corrosion resistaalce was due to galvamc cor- rosion, which resulted from the low area ratio of the cathode to anode regions. This caused a low-density corrosion current in the composite, thereby yielding optimum corrosion resistmlce.展开更多
基金Project(2013B090500091)supported by Industry-University-Research Combined Project of Guangdong Province,ChinaProject(20180358)supported by the Shenzhen Jiansheng Technology Inc.Cooperation Project,China。
文摘Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable.
基金financially supported by the National Natural Science Foundation of China(No.51364035)the Natural Science Foundation of Jiangxi Province(No.20171BAB206034)
文摘In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, sca^lning electron microscopy, mid energy diffraction spectroscopy. The results reveal that the c^-A1 phases were nearly spherical mid 40 gin in size and that the eutectic Si phases became round in the composite when the Sr content reached 0.2wt%. The A13Ti paxticles were distributed uniformly at the grain boundary. The results of the corrosion examination reveal that the A13Ti/ADC12 composite exhibited a minimum corrosion rate of 0.081 g.m 2,hl for an Sr content of 0.2wt%, which is two thirds of that of umnodified composite （0.134 g.m4.h 1）. This improved corrosion resistaalce was due to galvamc cor- rosion, which resulted from the low area ratio of the cathode to anode regions. This caused a low-density corrosion current in the composite, thereby yielding optimum corrosion resistmlce.
