P.K. Jena

Development of an ultrahigh strength low alloy steel for armour applications

Abstract The present paper describes a steel with yield strength exceeding 1900 MPa and fracture toughness in the range of 40–50 MPa m1/2, in its optimum heat treated condition. Its strength is similar to that of 18 Ni (300) grade of maraging steel with good fracture toughness. When tempered at 300°C, it shows tempered martensite along with a small amount of retained austenite phase. The steel shows nearly 25% reduction in weight over typical rolled homogeneous armour (RHA) steel against high velocity hard steel core projectiles. The processing, microstructure, mechanical and ballistic properties of the steel are demonstrated.

Effect of Texture on the Mechanical Properties and Ballistic Performance of an Extruded Al-6063 Rod

The present work describes the influence of texture and mechanical properties anisotropy on ballistic performance of an Aluminium-6063 extruded rod. It has been observed that the centre region of the extruded rod exhibits better strength, elongation and charpy impact values than the peripheral region. Texture of the extruded rod is measured from centre towards the periphery. A significantly variation in texture has been observed from the centre towards the periphery. Ballistic experiments are conducted on 80 mm thickness extruded samples by impacting them with 7.62 mm armour piercing projectile at 0° angle of impact at 840±15 m/s velocity. Results show that the centre of the extruded rod displays much improved ballistic performance than the periphery, which has been attributed to the strong {111} fibre texture present at the centre.

Effect of Tempering Temperature on Microstructure, Texture and Mechanical Properties of a High Strength Steel

This work describes the microstructure, texture and anisotropy in mechanical behavior of a high strength steel in various tempered conditions. The microstructures and mechanical properties change considerably with varying tempering temperatures. The material exhibits low in-plane anisotropy and low anisotropic index in terms of yield strength and elongation with increase in tempering temperature. The anisotropy of the material displays similar behavior to that of the yield strength.

Effect of Modes of Rolling on Mechanical Properties, Texture and Ballistic Performance of Al-7017 Alloy

This study describes the influence of texture and associated mechanical properties on ballistic performance of Aluminium-7017 alloy in two different (unidirectional and clock) hot rolling conditions. The change in texture has been explained in terms of β fiber in hot rolled and T6 tempered condition. A marginal variation in strength and hardness is observed with changing the mode of rolling, whereas Charpy impact values are found to be varying considerably. Results show that the unidirectional rolled material exhibits improved ballistic performance than that of the clock rolled plate. This has been attributed to different textures present in both the plates.