The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the t...The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the tensile strength and elongation subjected to different ultrasonic powers and solidification pressures. The results indicate that the synergistic action of ultrasonic vibration and solidification pressure can result in the refinement of grains and improvement of tensile properties. Both the highest tensile strength and elongation of aluminum alloy were obtained under synergistic action of 600 W ultrasonic power and 350 kPa solidification pressure. Moreover, the tensile fracture morphology shows obvious ductile fracture characteristics. When the solidification pressure is lower than 300 kPa, the effect of ultrasonic power on tensile strength and elongation is more obvious, but when the solidification pressure is higher than 300 kPa, the effect of solidification pressure on tensile strength and elongation is greater. Meanwhile, the size and morphology of the eutectic silicon were improved significantly by the ultrasonic vibration and pressurized solidification. The strip and massive eutectic silicon phase are completely converted into small short rod-like and evenly distributed Si phases at the grain boundary of primary α-Al.展开更多
To investigate the influence of Centrifugal Counter-gravity Casting(C3) process on the solidification microstructure and mechanical properties of the casting, A357 aluminum alloy samples were produced by different pro...To investigate the influence of Centrifugal Counter-gravity Casting(C3) process on the solidification microstructure and mechanical properties of the casting, A357 aluminum alloy samples were produced by different process conditions under C3. The results show that C3 has better feeding capacity compared with the vacuum suction casting; and that the mechanical vibration and the convection of melts formed at the centrifugal rotation stage suppress the growth of dendrites, subsequently resulting in the refinement of grains and the improvement of mechanical properties, density and hardness. A finer grain and higher strength can be obtained in the A357 alloy by increasing centrifugal radius and rotational speed. However, casting defects will appear near the rotational axis and the mechanical properties will decrease once the rotational speed exceeds 150 r·min-1.展开更多
目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定...目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定灌注泵流量0.2 L/min,灌注压力上限设定为100 mm Hg,吸引负压为10 k Pa,通过自制测压吸石输尿管扩张鞘副通道监测肾内压力,使用蚕食法边碎石边吸石,尽量将结石击碎至0.2 mm,术中根据视野清晰情况及肾内压力大小对灌注流量、压力及时进行调整。结果术中初始肾内压力为(14.7±3.2)mm Hg(9~22 mm Hg),灌注时间(29.3±2.5)min(25~37 min),术中视野清晰,无肾脏出血、破裂,术后生命体征平稳,无发热、尿源性脓毒血症等并发症,出院前1天复查腹部平片提示残留结石最大直径约1 cm 9例,0.5 cm 15例,<0.3 cm 9例,术后住院时间均为2天。术后1个月均返院取出双J管。术后2个月复查腹部平片及泌尿系B超,28例未见结石残留,5例见结石碎片残留于肾下极,直径<0.3 cm。结论本研究初步表明,使用自制测压吸石输尿管扩张鞘,手术过程安全,正负压力、进出流量可控,吸石效果良好。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51261025)the Aerospace Science and Technology Innovation Foundation of Shanghai,China(No.SAST2016046)the Key Projects of Superior Science and Technology Innovation Team of Jiangxi,China(No.20181BCB19001)
文摘The effect of synergistic action of ultrasonic vibration and solidification pressure on tensile properties of vacuum counter-pressure casting ZL114 A alloys was studied systemically through testing and analyzing the tensile strength and elongation subjected to different ultrasonic powers and solidification pressures. The results indicate that the synergistic action of ultrasonic vibration and solidification pressure can result in the refinement of grains and improvement of tensile properties. Both the highest tensile strength and elongation of aluminum alloy were obtained under synergistic action of 600 W ultrasonic power and 350 kPa solidification pressure. Moreover, the tensile fracture morphology shows obvious ductile fracture characteristics. When the solidification pressure is lower than 300 kPa, the effect of ultrasonic power on tensile strength and elongation is more obvious, but when the solidification pressure is higher than 300 kPa, the effect of solidification pressure on tensile strength and elongation is greater. Meanwhile, the size and morphology of the eutectic silicon were improved significantly by the ultrasonic vibration and pressurized solidification. The strip and massive eutectic silicon phase are completely converted into small short rod-like and evenly distributed Si phases at the grain boundary of primary α-Al.
基金financially supported by the National Natural Science Foundation of China(No.51375391)the Xi’an Municipal Science and Technology Bureau in China(No.CX12180(5))
文摘To investigate the influence of Centrifugal Counter-gravity Casting(C3) process on the solidification microstructure and mechanical properties of the casting, A357 aluminum alloy samples were produced by different process conditions under C3. The results show that C3 has better feeding capacity compared with the vacuum suction casting; and that the mechanical vibration and the convection of melts formed at the centrifugal rotation stage suppress the growth of dendrites, subsequently resulting in the refinement of grains and the improvement of mechanical properties, density and hardness. A finer grain and higher strength can be obtained in the A357 alloy by increasing centrifugal radius and rotational speed. However, casting defects will appear near the rotational axis and the mechanical properties will decrease once the rotational speed exceeds 150 r·min-1.
文摘目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定灌注泵流量0.2 L/min,灌注压力上限设定为100 mm Hg,吸引负压为10 k Pa,通过自制测压吸石输尿管扩张鞘副通道监测肾内压力,使用蚕食法边碎石边吸石,尽量将结石击碎至0.2 mm,术中根据视野清晰情况及肾内压力大小对灌注流量、压力及时进行调整。结果术中初始肾内压力为(14.7±3.2)mm Hg(9~22 mm Hg),灌注时间(29.3±2.5)min(25~37 min),术中视野清晰,无肾脏出血、破裂,术后生命体征平稳,无发热、尿源性脓毒血症等并发症,出院前1天复查腹部平片提示残留结石最大直径约1 cm 9例,0.5 cm 15例,<0.3 cm 9例,术后住院时间均为2天。术后1个月均返院取出双J管。术后2个月复查腹部平片及泌尿系B超,28例未见结石残留,5例见结石碎片残留于肾下极,直径<0.3 cm。结论本研究初步表明,使用自制测压吸石输尿管扩张鞘,手术过程安全,正负压力、进出流量可控,吸石效果良好。
