# Effect of Silicone Rubbers on the Properties of RDX-Based PBXs and Their Application in the Explosive Hardening of Steel

## TL;DR

This paper studies how silicone-based explosives can safely harden steel, showing improved mechanical properties and low sensitivity to mechanical triggers.

## Contribution

A novel silicone-based RDX PBX formulation is developed for explosive hardening with high detonation velocity and low sensitivity.

## Key findings

- The PBX achieved a detonation velocity of up to 7300 m/s and low mechanical sensitivity (10 J, 288 N).
- Explosive hardening increased the surface hardness of S235JR steel through grain fragmentation and recrystallization.
- The critical diameter of the PBX was measured at 3.3 mm, indicating good stability and safety.

## Abstract

Modern energetic materials (EMs) have many different civil applications. One of their most promising applications in civil engineering is explosive hardening, which facilitates the fast and cost-effective improvement of mechanical properties in the treated material. In this work, we present the results of our investigation on the explosive hardening of S235JR Steel with PBX formulations containing silicone binders and 1,3,5-trinitro-1,3,5-triazinane (RDX). In terms of safety, the impact (5–15 J) and friction (240–360 N) sensitivity of the tested plastic-bonded explosives (PBXs) was verified, simultaneously with DSC tests, energy of activation calculations, and critical diameter measurement. The developed material, prepared with techniques similar to the anticipated working conditions, is characterized by a high detonation velocity (up to 7300 m/s), low sensitivity for mechanical factors (10 J, 288 N), and a small critical diameter (3.3 mm). The developed PBX based on a silicone binder demonstrated grain fragmentation, recrystallization, and an increase in the surface hardness of S235JR steel, which was confirmed with SEM, EBSD, microstructure analysis, and microhardness studies.