Effect of Ti addition on the fracture toughness of Al-Ti-B alloys synthesized by high-energy ball milling and spark plasma sintering

摘要

Al alloys containing boron or its compound are attractive for neutron shielding materials since boron exhibits high thermal neutron absorbing capability. However, poor fracture toughness and low ductility of boron compounds restrict their usage as structural materials. By adding Ti as a third element, it is expected to improve the toughness of Al-B alloys. The present study investigates the effect of the Ti addition on fracture toughness of the (Al+Xat%Ti)2at%B (X=0.5,1,1.5 at%) alloy fabricated by high energy ball milling and spark plasma sintering (SPS). The SPS method was used to consolidate (Al+Xat%Ti)2at%B (X = 0.5,1,1.5 at%) alloy with the pressure of 50 MPa. Charpy impact tests showed that the fracture toughness of the 1 at%Ti added-alloy was 4 MPam~(1'2), and that it was three times higher than that of Al-B alloys. Further reduction of the Ti addition down to 0.5 at% at 1.9 MPam~(1/2) or up to 1.5 at% at 2 MPam~(1/2) slightly decreased the fracture toughness. The microstructures of the present specimens were investigated by FE-SEM and TEM to describe the relationship with fracture toughness.