The weldability of the ZhS6U nickel-based superalloy, which is prone to solidification cracking during electron-beam welding(EBW) repair processes, was investigated. The effects of two different pre-weld heat-treatmen...The weldability of the ZhS6U nickel-based superalloy, which is prone to solidification cracking during electron-beam welding(EBW) repair processes, was investigated. The effects of two different pre-weld heat-treatment cycles on the final microstructure before and after welding were examined. Welds were made on flat coupons using an EBW machine, and the two heat-treatment cycles were designed to reduce γ′ liquation before welding. Microstructural features were also examined by optical and scanning electron microscopy. The results showed that the change in the morphology and size of the γ′ precipitates in the pre-weld heat-treatment cycles changed the ability of the superalloy to release the tensile stresses caused by the matrix phase cooling after EBW. The high hardness in the welded coupons subjected to the first heat-treatment cycle resulted in greater resistance to stress release by the base alloy, and the concentration of stress in the base metal caused liquation cracks in the heat-affected zone and solidification cracks in the weld area.展开更多
THE area of present-day Zhejiang Province is one of the cradles of Chinese civ i l i zation.Human activities in the region can be traced back one million years,and more than 100 Neolithic sites have been discovered he...THE area of present-day Zhejiang Province is one of the cradles of Chinese civ i l i zation.Human activities in the region can be traced back one million years,and more than 100 Neolithic sites have been discovered here.Throughout recorded history,Zhejiang has always been a key administrative unit of China.During the Southern Song Dynasty(1127-1279),its capital was established in the present-day provincial capital of Zhejiang,Hangzhou,and many of the ports in this region served as major stops along the ancient Maritime Silk Road.展开更多
为明确抗除草剂转基因大豆ZH10-6对靶标除草剂草甘膦及几种常见除草剂的耐受性水平,在温室隔离条件下培养ZH10-6及其受体大豆中黄10,分别对其喷施不同浓度的茎叶处理剂草甘膦、乙羧氟草醚、精喹禾灵、2,4-滴二甲胺盐和土壤处理剂乙草胺...为明确抗除草剂转基因大豆ZH10-6对靶标除草剂草甘膦及几种常见除草剂的耐受性水平,在温室隔离条件下培养ZH10-6及其受体大豆中黄10,分别对其喷施不同浓度的茎叶处理剂草甘膦、乙羧氟草醚、精喹禾灵、2,4-滴二甲胺盐和土壤处理剂乙草胺,并对其药害症状、株高、干重等指标进行检测。结果表明:转基因大豆ZH10-6对靶标除草剂草甘膦具有较高的耐受性,在3600 g a.i./hm^(2)处理后28 d,株高、干重与对照无显著差异。而受体大豆中黄10在草甘膦900 g a.i./hm^(2)处理后14 d全部死亡。ZH10-6对大豆田常用除草剂乙羧氟草醚、精喹禾灵和乙草胺也有良好的耐受性,耐受性水平与中黄10无显著差异。转基因大豆ZH10-6及其受体大豆中黄10对2,4-滴二甲胺盐均表现敏感。展开更多
文摘The weldability of the ZhS6U nickel-based superalloy, which is prone to solidification cracking during electron-beam welding(EBW) repair processes, was investigated. The effects of two different pre-weld heat-treatment cycles on the final microstructure before and after welding were examined. Welds were made on flat coupons using an EBW machine, and the two heat-treatment cycles were designed to reduce γ′ liquation before welding. Microstructural features were also examined by optical and scanning electron microscopy. The results showed that the change in the morphology and size of the γ′ precipitates in the pre-weld heat-treatment cycles changed the ability of the superalloy to release the tensile stresses caused by the matrix phase cooling after EBW. The high hardness in the welded coupons subjected to the first heat-treatment cycle resulted in greater resistance to stress release by the base alloy, and the concentration of stress in the base metal caused liquation cracks in the heat-affected zone and solidification cracks in the weld area.
文摘THE area of present-day Zhejiang Province is one of the cradles of Chinese civ i l i zation.Human activities in the region can be traced back one million years,and more than 100 Neolithic sites have been discovered here.Throughout recorded history,Zhejiang has always been a key administrative unit of China.During the Southern Song Dynasty(1127-1279),its capital was established in the present-day provincial capital of Zhejiang,Hangzhou,and many of the ports in this region served as major stops along the ancient Maritime Silk Road.
文摘为明确抗除草剂转基因大豆ZH10-6对靶标除草剂草甘膦及几种常见除草剂的耐受性水平,在温室隔离条件下培养ZH10-6及其受体大豆中黄10,分别对其喷施不同浓度的茎叶处理剂草甘膦、乙羧氟草醚、精喹禾灵、2,4-滴二甲胺盐和土壤处理剂乙草胺,并对其药害症状、株高、干重等指标进行检测。结果表明:转基因大豆ZH10-6对靶标除草剂草甘膦具有较高的耐受性,在3600 g a.i./hm^(2)处理后28 d,株高、干重与对照无显著差异。而受体大豆中黄10在草甘膦900 g a.i./hm^(2)处理后14 d全部死亡。ZH10-6对大豆田常用除草剂乙羧氟草醚、精喹禾灵和乙草胺也有良好的耐受性,耐受性水平与中黄10无显著差异。转基因大豆ZH10-6及其受体大豆中黄10对2,4-滴二甲胺盐均表现敏感。
