Selective Laser Melted M300 Maraging Steel—Material Behaviour during Ballistic Testing

Significant growth in knowledge about metal additive manufacturing (AM) affects the increase of interest in military solutions, where there is always a need for unique technologies and materials. An important section of materials in the military are those dedicated to armour production. An AM material is characterised by different behaviour than those conventionally made, especially during more dynamic loading such as ballistics testing. In this paper, M300 maraging steel behavior was analysed under the condition of ballistic testing. The material was tested before and after solution annealing and ageing. This manuscript also contains some data based on structural analysis and tensile testing with digital image correlation. Based on the conducted research, M300 maraging steel was found to be a helpful material for some armour solutions after pre- or post-processing activities. Conducted solution annealing and ageing increased the ballistic properties by 87% in comparison to build samples. At the same time, the material’s brittleness increased, which affected a significant growth in fragmentation of the perforated plate. According to such phenomena, a detailed fracture analysis was made.

The Influence of Single and Double Steel Plate Hardness on Fracture Behavior after Ballistic Impact

This study aims to determine the ballistic characteristics of the two steel plates with different hardness levels and mix in the form of layered in non-permanent constructions. Ballistic testing by caliber 5.56 × 45 mm deformed full metal jacket on a sample plate with each a thickness of 6 mm at a distance of 15 m with a normal angle of attack. The results of ballistic testing on both single plates are they can be pierced by a projectile. While for the layered plate, projectile can only penetrate the front side of the plate. The characteristic of each hole that is formed shows the difference caused by the level of hardness of the plate. On the rear part of the plate, a bulge appears because of an impact from the front side of the plate. In the Soft Plate appear high petals around the hole on the front side with the microstructure deformed on the crater walls. While the hard plate forms small petals on the back side and slightly deformed crater walls. The Soft plate is perforated due to deformation with petaling and fragmentation mechanism, while the hard plate is perforated due to plugging mechanism and adiabatic shear band and cracked.

Lump System Analysis Modelling for Enhanced Ballistic Performance of Clay Box Doped with Different Types of Additives

The temperature of clay box used in the ballistic testing of body amour drops sharply upon removal from the oven. This implies that the clay has to be reinserted into the oven for another heating, which slows down the ballistic testing procedure. This paper attempts to solve the problem by studying the effect of addition of different percentages of rubber cuttings, saw dust and berley reeds additives on the cooling rate of clay used in clay box construction. The cooling rate is a measure of the ballistic performance of the clay box. The properties of the clay box such as the density, thermal conductivity and specific heat capacity are factored into the lump system analysis model. Minimum cooling rate of about 2.04×10-03 and 1.89×10-03oC/s were obtained when 0% and 10% rubber cuttings were used as dopands respectively. Rubber cuttings also proved to be the best additives that can be used to enhance the ballistic performance of clay box used in the ballistic testing of body armour.