Abstract
Grain refinement is a well-recognized method to simultaneously increase the strength and ductility of metallic materials.Fabrication of ultrafine-grained metals in bulk using a simple low-cost approach is a long-term goal for material scientists.In this work,based on the chemical composition of a biomedical Ti-15Zr alloy,a series of novel Ti-15Zr-xCu(x=0,3,5,7 wt.％)alloys were designed and fabricated.The alloys were quenched in the single β phase region to obtain a martensitic microstructure and deformed in the temperature range of 710-750℃to obtain an ultrafine-grained microstructure through marten-site decomposition under thermomechanical coupling conditions.Experimental results showed that Cu alloying could increase the dynamic recrystallization(DRX)nucleation rate due to its role in both re-fining martensitic lath width and increasing dislocation density.Cu alloying could also suppress grain growth due to the precipitated Ti2Cu particles exerting pinning forces on the grain boundaries.The op-timal Cu content in the Ti-15Zr-xCu alloy was determined to be 5 wt.％.After being subjected to a com-pression leading to a 70％height reduction at 730℃and 1 s-1,the grain size of the Ti-15Zr-5Cu alloy was only 180±70 nm.The tensile strength of the as-prepared alloy reached 975±10 MPa,which was 45％higher than that of the conventional Ti-15Zr alloy(673±16 MPa).This increase in strength was achieved without any reduction in ductility.The comprehensive mechanical properties of the ultrafine-grained Ti-15Zr-5Cu alloy are better than that of the Roxolid Ti-Zr alloy currently used for dental implants.
基金项目
国家重点研发计划(2018YFC1106601)
Doctoral Scientific Research Foundation of Liaoning Province(2020BS002)
NETL
NSTL
维普
万方数据