Performance Of Ti6Al4V Research Articles

Effect of the Layer Sequence on the Ballistic Performance and Failure Mechanism of Ti6Al4V/CP-Ti Laminated Composite Armor

The effect of the layer sequence on the ballistic performance of Ti6Al4V (35 mm)/CP-Ti (5 mm) laminated composite armor, against a 12.7 mm armor piercing projectile, was systematically investigated, both experimentally and computationally. By introducing the Johnson–Cook constitutive model and fracture criterion, the penetrating process of the composite plate was well-simulated. Furthermore, the influence of the layer sequence on the ballistic performance and failure mechanism of the composite plate was evaluated from the perspective of energy absorption and the stress distribution. Numerical simulation results of the macro morphology and penetration depth agreed well with the experimental results. The results showed that the energy absorption histories of each layer and stress distribution of the composite plate were found to be significantly affected by the arrangement sequence. The ballistic performance of Ti6Al4V/CP-Ti was far superior to that of CP-Ti/Ti6Al4V because more energy was absorbed in the early stage of the penetration process, thereby reducing the damage to the rear face. Further studies showed that the first principal stress in both structures was radially distributed in space, but was mainly concentrated at the rear face when the CP-Ti was placed at the front. Therefore, this stress induced cracking and failure in that region and, consequently, lowered the overall ballistic performance.

Effect of ultrasonic nanocrystalline surface modification on the water droplet erosion performance of Ti 6Al 4V

Abstract The effect of ultrasonic nanocrystalline surface modification (UNSM) on the water droplet erosion (WDE) performance of Ti 6Al 4V was studied. It was observed that UNSM induces deep levels of compressive residual stresses in both the scanning and transverse directions. The treated surface revealed microdimples in a micro-tracked fashion. Mechanical deformation marks were observed within the grains due to excessive plastic deformation and variation in grain size was observed across the ultrasonically modified layer. Microhardness of the UNSM condition was enhanced significantly as compared with the untreated (As-M) condition. The WDE performance tests for the UNSM and As-M conditions were conducted in a rotating disc rig in accordance with ASTM G73 standard. Influence of impact speed on WDE was explored on two different sample geometries (T-shaped flat and airfoil). WDE results showed that the flat UNSM samples had enhanced WDE performance at speeds 250, 275 and 300 m/s as compared with the As-M condition. At 350 m/s, both UNSM and As-M conditions showed similar performance. UNSM airfoil samples showed mild enhancement in the WDE performance at 300 m/s during the advanced stage as compared with the As-M condition. At 350 m/s, the UNSM airfoils do not show enhancement in WDE performance.

Effect of hot isostatic pressing procedure on performance of Ti6Al4V: Surface qualities, microstructure and mechanical properties

The effects of two different procedures (SL: simultaneous loading, AL: asynchronous loading) on the surface qualities, microstructure and mechanical properties of Ti6Al4V alloy part during hot isostatic pressing (HIP) were investigated. It was found that, in AL process, the surface qualities significantly improved. Both of microstructure were composed of equiaxed grains and lamellar structure, as well as the prior particle boundaries (PPBs) were clearly observed in SL process. Moreover, tensile strength of samples fabricated by the two different procedures was exactly similar. However, the fatigue limit of parts fabricated from AL process was higher than that of parts produced from SL process.

Sliding friction and wear performance of Ti 6Al 4V in the presence of surface-capped copper nanoclusters lubricant

The friction and wear properties of Ti 6Al 4V sliding against AISI52100 steel ball under different lubricative media of surface-capped copper nanoclusters lubricant—Cu nanoparticles capped with O, O′-di- n-octyldithiophosphate (Cu-DTP), rapeseed oil and rapeseed oil containing 1 wt% Cu-DTP was evaluated using an Optimol SRV oscillating friction and wear tester. The wear mechanism was examined using scanning electron microscopy (SEM) and X-ray photoelectron spectrosmeter (XPS). Results indicate that Cu-DTP can act as the best lubricant for Ti 6Al 4V as compared with rapeseed oil and rapeseed oil containing 1 wt% Cu-DTP. The applied load and sliding frequency obviously affected the friction and wear behavior of Ti 6Al 4V under Cu-DTP lubricating. The frictional experiment of the Ti 6Al 4V sliding against AISI52100 cannot continue under the lubricating condition of rapeseed oil or rapeseed oil containing 1 wt% Cu-DTP when the applied load are over 100 N. Surprisingly, the frictional experiment of Ti 6Al 4V sliding against AISI52100 steel can continue at the applied load of 450 N under Cu-DTP lubricating. The tribochemical reaction film containing S and P is responsible for the good wear resistance and friction reduction of Ti 6Al 4V under Cu-DTP at the low applied load. However, a conjunct effect of Cu nanoparticle deposited film and tribochemical reaction film containing S and P contributes to the good tribological properties of Ti 6Al 4V under Cu-DTP at the high-applied load.