Evaluation of superelastic nitinol as a shielding material for hypervelocity impact
Espinoza Magana, Nancy
Barrera, Enrique V.
Master of Science
Superelastic Nitinol Shape Memory Alloy (SMA) as a shielding material for hypervelocity impact is investigated. Impact peak pressures from Rankine-Hugoniot equations and empirical figures of merit, which give a general evaluation of this material as a nickel titanium alloy, have been derived. Superelastic Nitinol was impacted at oblique and normal incidence using a two-stage light-gas gun and was evaluated as an intermediate layer in the Stuffed Whipple configuration and as bumper in the Whipple configuration. Its performance during oblique impacts is better than that of Kevlar and Al2024-T3. Superelastic SMA can dissipate impact energy through a martensitic phase transformation and through plastic yielding. Differential scanning calorimeter studies demonstrated that stress induced Martensite (SIM) is present in the hypervelocity impacted samples. Optical metallography and electron microscopy studies confirm the presence of SIM.
Aerospace engineering; Materials science