新型高密度合金的组织与性能

A new high density alloy NiW750 was developed, which was based on the faced-center cubic solid solution structure and aging strengthening mechanism. Microstructure of the alloy was observed by SEM and TEM. The material characteristics under dynamic compressing loading were investigated by using the split Hopkinson pressure bar test. The comparison among the NiW750, ultra high strength steel G50 and tungsten 93WNiFe was also conducted.The results show that the NiW750 high density alloy has the best comprehensive properties among three materials. After aging at 750℃/5h, the tensile strength of NiW750 can achieve up to 1746MPa, while the impact toughness (a_kU) can achieve 113J/cm². Under the condition of dynamic loading, the material shows strain rate hardening effect obviously as its dynamic flow stress can reach about 2250MPa. The adiabatic shear bands are formed within specimens in the direction of 45° to the central axis with a bandwidth of 80-150μm at the strain rate of about 5500s^-1 and a wide transition zone, so as to avoid the premature emergence of the shear fracture.