E-Book Overview
The institute of Electrical Engineers of Japan Transactions on Fundamentals and Materials Vol. 125, No.9, 2005, pp. 744-748.
A complementary study on experimental observation and theoretical modeling has been performed to investigate the ablation behavior on titanium irradiated by high-intensity pulsed ion beams (HIPIB) with energy density of 70 J/cm2 up to 3 shots. The surface morphology with a typical waviness feature on the irradiated surface was observed by scanning electron microscopy (SEM). The observed surface morphology indicates a severer ablation in the center of irradiated area, leading to a fluctuation of liquid layer spreading radially to the peripheral area, due to the spatial distribution of ion beam energy density along the radial direction. The ablation process was simulated from the modeling of heat transfer in the irradiated samples using an axisymmetric model based on enthalpy formulation. The computational results are in good agreement with the experimental findings in the ablation mass with a trend of severer ablation in the center of irradiated area.
E-Book Content
Paper Ablation Behavior of Titanium Irradiated by High-Intensity Pulsed Ion Beams Shoumou Miao＊ Xiaopeng Zhu＊＊ Mingkai Lei＊ Hisayuki Suematsu＊＊ Weihua Jiang＊＊ Kiyoshi Yatsui＊＊ Non-member Non-member Non-member Member Member Member A complementary study on experimental observation and theoretical modeling has been performed to investigate the ablation behavior on titanium irradiated by high-intensity pulsed ion beams (HIPIB) with energy density of 70 J/cm2 up to 3 shots. The surface morphology with a typical waviness feature on the irradiated surface was observed by scanning electron microscopy (SEM). The observed surface morphology indicates a severer ablation in the center of irradiated area, leading to a fluctuation of liquid layer spreading radially to the peripheral area, due to the spatial distribution of ion beam energy density along the radial direction. The ablation process was simulated from the modeling of heat transfer in the irradiated samples using an axisymmetric model based on enthalpy formulation. The computational results are in good agreement with the experimental findings in the ablation mass with a trend of severer ablation in the center of irradiated area. Keywords : High-intensity pulsed ion beam, ablation, modeling, surface morphology, titanium ablation mass of irradiated Ti samples have been observed and measured, respectively, and also been modeled using a two-dimensional axisymmetric numerical model based on enthalpy formulation, in order to explore the interaction mechanism of HIPIB with materials. 1. Introduction The high-intensity pulsed ion beams (HIPIB) efficiently deliver energy onto materials in the ion range (0.1-10 µm) during a short pulse width (τ ≤ 1 µs) to rapidly melt and strongly vaporize (or ablate) the near-surface layer of materials (1). The plasma plume formed by HIPIB ablation expands away from the ablated surface and generates strong shock stress in the irradiated materials. These nonequilibrium processes led to a significant change in composition, microstructure and morphology on the irradiated materials, affecting the performance of materials. The understanding of ablation behavior on the surface irradiated by HIPIB is very helpful to explore the interaction mechanism of HIPIB with materials. However, experimental observation during HIPIB irradiation is limited due to the extreme high-density energy in a short pulse width, and thus the observation of surface morphology after irradiation is being considered as a useful means (2)-(5). Meanwhile, theoretical modeling is desired according to the numerical analysis of heat transfer on surface irradiated by HIPIB, though the process of heat transfer in substrate is mainly simulated by an one-demen