# Effects of TC4 Thickness on the Penetration Resistance Behavior of Ti-Al3Ti Metal–Intermetallic Laminated Composites

## TL;DR

This study shows that increasing the thickness of titanium layers in Ti-Al3Ti metal composites significantly improves their resistance to high-speed penetration.

## Contribution

The novel contribution is demonstrating that millimeter-thick Ti layers enhance anti-penetration performance through controlled crack propagation and interface failure.

## Key findings

- A 2.5 mm Ti layer reduces projectile residual velocity by up to 100% at 600 m/s impact.
- Thicker Ti layers increase crack propagation angles, improving energy absorption.
- Stress wave propagation analysis reveals enhanced performance via ductile layer thickness.

## Abstract

Ti-Al3Ti metal–intermetallic laminate (MIL) composites with microscale layer thickness have attracted attention in aerospace applications. However, whether millimeter-thick Ti layers can enhance the anti-penetration of Ti-Al3Ti MIL composites under 400–1000 m/s impact velocities remains unclear. In this study, a Ti-Al3Ti MIL composite target was prepared by hot press sintering, and the 2D finite element model validated by anti-penetration testing was used to prove that increasing the thickness of the Ti layer significantly increases the stress level and anti-penetration limit of the target. Simulations show that compared with a 0.1 mm Ti layer, a 2.5 mm Ti layer reduces the projectile residual velocity by 100% (600 m/s), 72% (800 m/s), and 38.5% (1000 m/s). With a total thickness difference of 0.1 mm, the crack propagation angles increase by 4° (0.06 mm Ti) and 14° (2.5 mm Ti) compared to a 0.4 mm Ti layer. By analyzing stress wave propagation and energy absorption during penetration, this work reveals that millimeter-thick Ti layers improve anti-penetration performance by controlling heterogeneous interface failure and the crack propagation direction through increased ductile layer thickness. These findings provide data for MIL composites and offer potential cost reductions for high-performance anti-penetration materials.