Study On Aging Mechanism And Dynamic Mechanical Behavior Of Nickel-tungsten High Density Alloy

The penetration warhead requires material with high strength,high toughness,high density and the excellent dynamic response capability under high-speed impact.With the development of the penetration demand,the project to find a new material of the penetration warhead is of practical significance.The DT750 nickel-tungsten high-density alloy studied in this paper is a ni-tungsten binary alloy based on Ni₁₇W₃,which shows excellent properties such as high density,high plasticity and high strength.According to its application background,this paper studies the DT750 nickel tungsten high density alloy as follows:?1?In order to obtain a higher strength nickel tungsten alloy material,it was aged at 700�C for 5 hours,10 hours and 15 hours.The effect of aging treatment on the mechanical properties of DT750 nickel tungsten alloy was obtained by quasi-static tensile test.The phase composition analysis was taken by XRD and morphology analysis was taken by OM.Finally,the strengthening mechanism was disscussed.The experimental results show that the strength of the alloy material increases with the aging time after the aging treatment of the DT750 nickel tungsten alloy at 700?.The plasticity decreases rapidly with the aging time.It was found that the grain size of the alloy was not changed after aging treatment by OM.The macroscopic phase composition of DT750 nickel tungsten alloy before and after aging was not changed obviously according to XRD patterns.The Ni₄W intermetallic compound was observed by transmission electron microscopy?TEM?in DT750 sample after the aging treatment.Because of the presence of the tetragonal-structure Ni4W the strength was improved,The distribution and size of Ni₄W in the treated DT750 alloy was observed by dark field imaging.?2?In order to study the deformation and failure mechanism of DT750 nickel tungsten alloy under high strain rate load,the dynamic mechanical properties of DT750 nickel tungsten alloy and Ni-27W alloy were testedby the Hopkinson dynamic bar.After tested the microstructure evolution was observed.The experimental results show that the shear failure of the original Ni-W alloy at 6000s^-1 strain rate.The second phase W in the alloy can effectively improve the strength of the nickel-tungsten alloy,while almost no influence of plastic properties.The dynamic strength of the Ni-W alloy increases with the aging time at700?after aging at different times.When the aging time is less than 10 hours,the plasticity of the material does not change obviously.When the aging time is higher than 10 hours,the plasticity of the material decreases rapidly The This is due to the presence of Ni4W intermetallic compounds in the alloy with time incresasing.