Abstract Laser shock peening (LSP) of Al2O3 armour ceramics is reported for the first-time. A 10 J, 8 ns, pulsed Nd:YAG laser with a 532 nm wavelength was employed. The hardness, KIc, fracture morphology, topography, surface residual stresses and microstructures were investigated. The results showed an increase in the surface hardness by 10% which was confirmed by a reduction in Vickers indentations size by 5%. The respective flaw sizes of the Vickers indentations were also reduced (10.5%) and inherently increased the KIc (12%). Residual stress state by X-ray diffraction method showed an average stress of − 64 MPa after LSP, whilst the untreated surface stress measured + 219 MPa. Further verification with the fluorescence method revealed surface relaxation with a maximum compressive stress of − 172 MPa induced after LSP within the Al2O3 armour ceramic. These findings are attributed to a microstructural refinement, grain size reduction and an induction of compressive stress that was relaxing the top/near surface layer (post LSP) from the pre-existing tensile stresses. Further process refinement/optimization will provide better control of the surface properties and will act as a strengthening technique to improve the performance of armour ceramics to stop bullets for a longer period of time and protect the end-users.

中文翻译：

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表面工程氧化铝装甲陶瓷，采用激光冲击强化，以提高硬度、断裂韧性、微观结构和压缩残余应力

摘要 首次报道了Al2O3装甲陶瓷的激光冲击强化(LSP)。采用 10 J、8 ns、532 nm 波长的脉冲 Nd:YAG 激光器。研究了硬度、KIc、断口形貌、形貌、表面残余应力和微观结构。结果表明表面硬度增加了 10%，这通过维氏压痕尺寸减少 5% 得到证实。维氏压痕的相应缺陷尺寸也减少了 (10.5%) 并固有地增加了 KIc (12%)。X 射线衍射法的残余应力状态显示 LSP 后的平均应力为 - 64 MPa，而未处理的表面应力测量值为 + 219 MPa。用荧光法进一步验证表明，在 Al2O3 装甲陶瓷内 LSP 后诱导的最大压应力为 - 172 MPa 的表面松弛。这些发现归因于微观结构的细化、晶粒尺寸的减小和压缩应力的诱导，这些压缩应力使顶部/近表面层（后 LSP）从预先存在的拉伸应力中松弛下来。进一步的工艺改进/优化将更好地控制表面特性，并将作为一种强化技术来提高装甲陶瓷的性能，以在更长的时间内阻止子弹并保护最终用户。晶粒尺寸减小和压缩应力的诱导使顶部/近表面层（后 LSP）从预先存在的拉伸应力中松弛。进一步的工艺改进/优化将更好地控制表面特性，并将作为一种强化技术来提高装甲陶瓷的性能，以在更长的时间内阻止子弹并保护最终用户。晶粒尺寸减小和压缩应力的诱导使顶部/近表面层（后 LSP）从预先存在的拉伸应力中松弛。进一步的工艺改进/优化将更好地控制表面特性，并将作为一种强化技术来提高装甲陶瓷的性能，以在更长的时间内阻止子弹并保护最终用户。