Growth of Single Crystals of High-purity Metals by Electron-beam Zone Melting
For effective malting and growing, the original EB guns as well as the EBFZM setups were elaborated.Several versions of the original work-accelerating EB guns which are the most im portant dement of the EBFZM setups were tested in growing different kinds of single crystals of refracto ry metals in the time period of more than forty years.The dislocation substructures of single crys tals of Mo and W are characterized by significant similarity and remain virtually unchanged at the growth rates of 0.5-5 mm/min.Significant chan ges in the substructure, reflected in increasing frag mentation of the subgrains and the misorientation angles of up to 3-40 of an arc, take place when the growth rates increase to 10-20 mm/min and a bove.Mter sudden increase of the growth rates from 2 mm/min to 40 mm/min, the dislocation den sity inside the subgrains increases on an order of magnitude, reaching 5· 106 cm-2.Due to the high temperature gradients near the crystallization front and the high cooling rates, the growth of the perfect single crystals of Mo and W from the melt is impos sible.The conditions of the growth of single crystals with the ultimately low dislocation density and the small subgrains spread are revealed.The relatively low dislocation density and the lack of the smallangle boundaries are achieved by recrystallization.The optimal procedure involves the 6 % deformation of the single crystalline specimen with the < 111 >growth axis by rolling in vacuum along the < 112 > plane and in-situ high-temperature annealing.
Vadim Glebovsky
Institute of Solid State Physics,the Russian Academy of Sciences Chernogolovka,142432 Russia
国际会议
The 12th China-Russia Symposium on Advanced Materials and Technologies(第十二届中俄双边新材料新工艺国际会议)
昆明
英文
514-518
2013-11-19（万方平台首次上网日期，不代表论文的发表时间）