THE EFFECT OF beta-STABILIZING ELEMENTS ON THE TENSILE STRAIN BEHAVIOR OF SINGLE alpha-TYPE Ti-ALLOYS AT 20K

摘要

In the present work, a single alpha-phase alloy and a near alpha-phase alloy with a little amount of beta-stabilizing elements, the microstructure of them is very different, were selected for investigation on tensile strain behavior at 300K and 20K. The tensile tested results showed that in both alloys, the tensile curves at 20K became serrated, and the number of serration corresponds with the number of necking in the specimen gage section. While in the microstructure of tensile strained at 20K, there were a large number of deformation twins in the single alpha-phase alloy, but in the near-alpha-phase alloy, it is hardly to find deformation twins. These results suggest that the serration of the tensile curve is not directly related with the deformation twins appeared in the tensile strained microstructure, and is real deal with the necking in the specimen gage section. Some reasons probably caused multiple necking are discussed in the paper.