Influences of some treating ways

such as untreated

alloying treatment of P and La

ultrasonic treatment and compound treatment of ultrasonic and alloying

on solidification structure and mechanical properties of Al-20Mg

2

Si were investigated.Effects of ultrasonic power

ultrasonic treatment time and ultrasonic treatment temperature on size of Mg

2

Si phase and mechanical properties of the alloy were investigated under the condition of compound treatment.The results reveal that after compound treatment

the solidification structure and mechanical properties of the alloy are improved remarkably

and the effects are superior to those of single alloying treatment or ultrasonic treatment.Compared with untreated samples

the size of the primary Mg

2

Si phase is decreases by 68%

and the tensile strength and elongation of the alloy are increased by 62.3%and 47%

respectively.With the increase of ultrasonic power

the size of primary Mg

2

Si phase is decreased gradually

and the mechanical properties are increased gradually.With the increase of ultrasonic treatment time

the size of primary Mg

2

Si phase is decreased at first and then increased

however

the mechanical properties of the alloy are increased gradually.With the increase of ultrasonic treatment temperature

the size of primary Mg

2

Si phase is decreased at first and then increased

and the change rule of mechanical properties of the alloy is corresponded with it.