Effect Of Pulsed Ultrasound On The Microstructure And Mechanical Properties Of ZL205A Alloy Melt

The high strength and excellent comprehensive performance of ZL205 A alloy has been widely used in the field of aerospace.However,the casting performance of ZL205 A alloy is poor,it is easy to produce shrinkage cavity,shrinkage porosity and other defects.Ultrasonic melt treatment technology is a kind of high efficiency and non-polluting technology,it is used to improve the microstructure and the performance of the alloy.At the same output power,the sound pressure amplitude of pulsed ultrasound is higher than ordinary continuous ultrasound,so the microstructure of alloy may be more improved by the pulsed ultrasound.Therefore,the effect of pulsed ultrasound on the microstructure and mechanical properties of ZL205 A alloy melt was studied,and the pulse ultrasonic technology was optimized to provide the theoretical basis and technical support for the application of pulsed ultrasonic in the application of aluminum alloy melt.It takes the ZL205 A alloy as the research object,the effects of pulsed ultrasonic power?pulsed frequency and ultrasonic vibration time on the microstructure and mechanical properties of ZL205 A alloy melt were investigated.The solidification mechanism of aluminum alloy under pulsed ultrasound was discussed.The results indicated that the effect of pulsed ultrasound on the microstructure and mechanical properties of ZL205 A alloy melt was significant.With the increase of pulsed ultrasonic power?pulsed frequency and ultrasonic vibration time,the microstructure of ZL205 A alloy first became thinner and then became coarser,meanwhile the grain size of ZL205 A alloy first decreased and then increased.The tensile strength and elongation of ZL205 A alloy first increased then decreased with the increase of pulsed ultrasonic power?pulsed frequency and ultrasonic vibration time.The optimum process parameters of ZL205 A alloy under pulsed ultrasound were 1200 W pulsed ultrasonic power?1.67 HZ pulsed frequency?120s ultrasonic vibration time.Under the best pulsed ultrasonic process,the grain size of ZL205 A alloy was 182.43?m,the tensile strength and elongation were 385.4Mpa?3.1%.The content of Cu element in the ZL205 A alloy was measured under different pulsed ultrasonic parameters with EDS results.The effect of pulsed ultrasound on the microsegregation of Cu element in the ZL205 A alloy was investigated.The results indicated that the effect of pulsed ultrasonic power and ultrasonic vibration time on the microsegregation of Cu element in the ZL205 A alloy was significant,and the effect of pulsed frequency was smaller.The concentration profiles of Cu element increased due to the effect of pulsed ultrasound,and the effective distribution coefficient ke of Cu element was also increased.The distribution of Cu element in the aluminum alloy was improved under the pulsed ultrasound.The results of the study provided the theoretical and technical basis for the application of pulsed ultrasound in the melt of aluminum alloy,which was important to the theoretical and practical significance.