By adding different amounts of Ti into the electromagnetic stirred Al-18wt.%Mg_(2)Si alloy,the effect of Ti element on the microstructure and mechanical properties of the alloy was studied.The experimental results sho...By adding different amounts of Ti into the electromagnetic stirred Al-18wt.%Mg_(2)Si alloy,the effect of Ti element on the microstructure and mechanical properties of the alloy was studied.The experimental results show that the microstructure is refined after modification with Ti,which is related to the heterogeneous nucleation of TiAl_(3) particles on theα-Al matrix.With the increase of Ti content and holding time after stirring,the primary Mg_(2)Si phase is refined firstly and then coarsened,and correspondingly,the mechanical properties of the alloy show a trend of increasing at first and then decreasing.When the addition of Ti is 0.5wt.%and the holding time is about 20 min,the refinement effect of primary Mg_(2)Si phase is the most significant and the mechanical properties of the alloy are optimal.展开更多
The effects of Sb and Sr on the modification and refinement of Mg_(17)Al_(12)and Mg_2Si phases in Mg-12Al-0.7Si alloy were investigated and compared. The microstructure and mechanical properties of Mg-12Al-0.7Si alloy...The effects of Sb and Sr on the modification and refinement of Mg_(17)Al_(12)and Mg_2Si phases in Mg-12Al-0.7Si alloy were investigated and compared. The microstructure and mechanical properties of Mg-12Al-0.7Si alloy and its modification mechanism by Sb and Sr were investigated using a scanning electron microscope(SEM), an energy dispersive spectrometer(EDS), X-ray diffraction(XRD) and differential thermal analysis(DTA). The results indicate that by adding 0.5wt.% Sb to the Mg-12Al-0.7Si alloy, the Mg_(17)Al_(12)phase was refined and broken into some discontinuous island structures. However, some network Mg_(17)Al_(12)phases still can be detected in Mg-12Al-0.7Si-0.09 Sr alloy. Therefore, Sb performs better in modification and refinement of Mg_(17)Al_(12)phase than does Sr. Small amounts of fine polygonal shaped Mg_2Si phases were found in Mg-12Al-0.7Si-0.5Sb alloy, while the morphology of Mg_2Si phases in Mg-12Al-0.7Si-0.09 Sr alloy changed from the coarse Chinese script shapes to fine granule and irregular polygonal shapes, indicating that the effects of modification and refinement on Mg_2Si phase are more significant by adding 0.09 wt.% Sr than 0.5wt.% Sb. The ultimate tensile strengths of the Sb and Sr modified Mg-12Al-0.7Si alloys were considerably increased both at room temperature and at 200 oC.展开更多
基金financially supported by the Science and Technology Development Program of Shouguang(No.2019JH14)the Science and Technology Development Program of Weifang(No.2021GX052)the Natural Science Foundation of Liaoning Province(No.080137)。
文摘By adding different amounts of Ti into the electromagnetic stirred Al-18wt.%Mg_(2)Si alloy,the effect of Ti element on the microstructure and mechanical properties of the alloy was studied.The experimental results show that the microstructure is refined after modification with Ti,which is related to the heterogeneous nucleation of TiAl_(3) particles on theα-Al matrix.With the increase of Ti content and holding time after stirring,the primary Mg_(2)Si phase is refined firstly and then coarsened,and correspondingly,the mechanical properties of the alloy show a trend of increasing at first and then decreasing.When the addition of Ti is 0.5wt.%and the holding time is about 20 min,the refinement effect of primary Mg_(2)Si phase is the most significant and the mechanical properties of the alloy are optimal.
基金financially supported by the National Natural Science Foundation of China(Grant nos.:51301118,51404166)the Projects of International Cooperation in Shanxi province,China(Grant no.:2014081002)and the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi province,China(Grant nos.:2013108,2014120)
文摘The effects of Sb and Sr on the modification and refinement of Mg_(17)Al_(12)and Mg_2Si phases in Mg-12Al-0.7Si alloy were investigated and compared. The microstructure and mechanical properties of Mg-12Al-0.7Si alloy and its modification mechanism by Sb and Sr were investigated using a scanning electron microscope(SEM), an energy dispersive spectrometer(EDS), X-ray diffraction(XRD) and differential thermal analysis(DTA). The results indicate that by adding 0.5wt.% Sb to the Mg-12Al-0.7Si alloy, the Mg_(17)Al_(12)phase was refined and broken into some discontinuous island structures. However, some network Mg_(17)Al_(12)phases still can be detected in Mg-12Al-0.7Si-0.09 Sr alloy. Therefore, Sb performs better in modification and refinement of Mg_(17)Al_(12)phase than does Sr. Small amounts of fine polygonal shaped Mg_2Si phases were found in Mg-12Al-0.7Si-0.5Sb alloy, while the morphology of Mg_2Si phases in Mg-12Al-0.7Si-0.09 Sr alloy changed from the coarse Chinese script shapes to fine granule and irregular polygonal shapes, indicating that the effects of modification and refinement on Mg_2Si phase are more significant by adding 0.09 wt.% Sr than 0.5wt.% Sb. The ultimate tensile strengths of the Sb and Sr modified Mg-12Al-0.7Si alloys were considerably increased both at room temperature and at 200 oC.
