Microstructural evolution and mechanical properties response of the ZT40 alloy with hot rolling

Abstract

The Zr-40Ti-4.5Al-4.2V (ZT40) alloy is one of new developed Zirconium alloys with high mechanical properties and great potential for application. The investigation about effects of plastic deformation on microstructure and mechanical properties can promote practical applications of the new high performance ZrTi based alloys. The microstructural evolution and mechanical properties of the ZT40 alloy suffered hot rolling with thickness reduction from 30% to 60% at 775 °C are investigated in this work. Results show that the phase constitution changes from (α + β) to (β + fcc) while the original specimen underwent hot rolling and subsequent water quenching. The β phase in hot rolled specimen adopts preferred orientation form (200) and (211) planes to only (200) plane while the rolling reduction increases from 30% to 60%. Furthermore, no obvious preferred orientation can be detected in specimen with reductions of 60%. Micrographs analysis shows that the dynamic recrystallization occurs in hot rolled specimens. Volume fraction of the DRX grains is approximately 8% in 30% reduction specimen and increases with the increasing of rolling reduction. Nearly full recrystallization is observed in the specimen with reductions of 60%. Hardness test shows that the HV of hot rolled specimen decreases from 384 HV to 329 HV as the increasing of reduction from 30% to 60%. The mechanisms of microstructural evolution and variation of hardness are also discussed. The finding should contribute to understand microstructural evolution, to adjust mechanical properties and to promote practical applications of Zirconium alloys.