Yu Yun

Effects of hydrogen in lanthanum on hydrogen content in Al-alloy

Abstract The effects of lanthanum on hydrogen content in Al–Si alloy are investigated by Degle method and other methods. The results indicate that the hydrogen content in liquid aluminum alloy has been considerably increased after adding than 0.3% lanthanum, the defects of the needle holes in solidification samples under negative and standard pressure also increase. The relationships between hydrogen content in liquid aluminum alloy and the time after adding lanthanum present two different processes: the increase and decrease of the calculated hydrogen in Al-alloy melt. The hydrogen in lanthanum is the main reason for the results. The X-diffraction spectrum of lanthanum indicates that the starting lanthanum contains small quantity hydrides. The relationships between the addition of lanthanum and the resulting hydrogen concentration in liquid Al-alloy are also discussed.