Effects of La Microalloying on Hot Deformation Behavior and Microstructure Law of Al-Si Alloy

Al-Si alloys without La and with a La content of 0.068% were prepared by melting casting method. Two types of AlSi-（La） alloys were subjected to isothermal hot compression tests, with hot deformation temperatures of 300 ℃ and 400 ℃,and strain rates of 0.01 s^-1 and 0.1 s^-1, respectively. The hot deformation behavior of the alloys was studied. The effects of different La contents on the microstructure and mechanical properties of Al-Si-La alloys during hot deformation were studied using metallographic microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, energy spectrum analysis, and hardness tester. The results show that the flow stress of both alloys decreases with the increase of deformation temperature and the decrease of strain rate. The Al-Si alloy with La added exhibits a stable flow state under hot deformation conditions of 300 ℃ and 0.1 s^-1, and the addition of La increases the peak stress of the alloy. The addition of La can generate Al Si La metal intermetallic compounds, which optimize the morphology and size of the eutectic Si phase, and increase the hardness of the hot deformed Al-Si alloy.