Microstructural evolution of the in situ Al-15wt.%Mg2Si composite with extra Si contents
Microstructural evolution of the in situ Al-15wt.%Mg2Si composite with extra Si contents
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DOI：
10.1016/s1359-6462(00)00338-9
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发表时间：
2000-05
影响因子：
6
通讯作者：
Junpei Zhang;Z. Fan;Y. Q. Wang;B. Zhou
中科院分区：
文献类型：
--
作者：
Junpei Zhang;Z. Fan;Y. Q. Wang;B. Zhou
讨论在体系中加入不同量的Si后，所得的显微组织发生了显著的变化。如图3所示计算Al-Mg-Si三元相图中从Al-15 Mg 2 Si到Si的平衡垂直截面（沿着图2中示意性示出的虚线），其对应于本实验中的组成变化。由图3可知，随着Si含量的增加，合金的平衡凝固路径由（1）变为（3），这取决于合金的成分：（1）Al-15 Mg 2Si-（0-a）Si：L→ L1 + Mg 2Sip → L2 +（Al+ Mg 2 Si）E+ Mg 2 Si p→（Al+ Mg 2 Si）E+ Mg 2 Si p（2）Al-15 Mg 2 Si-（ab）Si：L→ L1 + Mg 2 Si p→ L2 +（Al+ Mg 2 Si）E+ Mg 2 Si p→（Al+ Si+ Mg 2 Si）E+（Si+ Mg 2 Si）E+ Mg 2 Si p（3）Al-15 Mg 2 Si-（ab）Si：L→ L1 + Mg 2 Si p→ L2 +（Si+ Mg 2 Si）E+ Mg 2 Si p→（Al+ Si+ Mg 2 Si）E+（Si+ Mg 2Si）E+ Mg 2Sip其中下标p表示初级颗粒，E表示共晶，a，B和c表示如图3中标记的组成范围。因此，在所有情况下，Mg 2Si初级颗粒将从液体中凝固，然后通过二元共晶反应形成Al或Si与Mg 2Si的共晶。然后，如果额外的Si含量在图3中的a至c的范围内，则将形成三元共晶。
DiscussionWith different extra Si additions in the system, the resulting microstructure changed dramatically. The equilibrium vertical section from Al-15Mg 2 Si to Si in the Al-Mg-Si ternary phase diagram (along the dash line as schematically illustrated in Fig. 2) was calculated as shown in Fig. 3, which corresponds to the composition change in the present experiment. According to Fig. 3, with the increase in Si content, the equilibrium solidification paths of the alloys will change from (1) to (3) depending on the alloy compositions,,:(1) Al-15Mg 2 Si-(0-a) Si: L→ L 1+ Mg 2 Si p→ L 2+(Al+ Mg 2 Si) E+ Mg 2 Si p→(Al+ Mg 2 Si) E+ Mg 2 Si p (2) Al-15Mg 2 Si-(ab) Si: L→ L 1+ Mg 2 Si p→ L 2+(Al+ Mg 2 Si) E+ Mg 2 Si p→(Al+ Si+ Mg 2 Si) E+(Si+ Mg 2 Si) E+ Mg 2 Si p (3) Al-15Mg 2 Si-(ab) Si: L→ L 1+ Mg 2 Si p→ L 2+(Si+ Mg 2 Si) E+ Mg 2 Si p→(Al+ Si+ Mg 2 Si) E+(Si+ Mg 2 Si) E+ Mg 2 Si p where the subscript p represents the primary particle, E represents the eutectic, a, b and c indicate the composition range as marked in Fig. 3. Accordingly, Mg 2 Si primary particles will solidify from the liquid in all cases followed by binary eutectic reactions to form either Al or Si eutectic with Mg 2 Si. Afterwards, the ternary eutectic will form if extra Si content in the range from a to c in Fig. 3.