Bonding, Reactivity, and Mechanical Properties of the Kinetic-Sprayed Deposition of Al for a Thermally Activated Reactiv
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JTTEE5 23:818–826 DOI: 10.1007/s11666-014-0088-z 1059-9630/$19.00 ASM International
Bonding, Reactivity, and Mechanical Properties of the Kinetic-Sprayed Deposition of Al for a Thermally Activated Reactive Cu Liner Juyeon Won, Gyuyeol Bae, Kicheol Kang, Changhee Lee, See Jo Kim, Kee-Ahn Lee, and Seong Lee (Submitted December 27, 2012; in revised form January 22, 2014) Pure Al coatings were fabricated on Cu substrates via kinetic spraying to produce a thermally activated reactive Cu liner. The coatings need to endure high-strain rate severe plastic deformation and react with oxygen during penetration or after penetration of the liner. In this study, the Al powder underwent large exothermic reactions with a small particle size and fast heating rate, as determined from the differential scanning calorimetric analysis. Process optimization of the Al deposition was facilitated by defining the ‘‘critical velocity’’ of an Al particle in the kinetic spraying process based on numerical modeling and computations using ABAQUS finite element codes. The simulation results revealed that the critical velocity of an Al particle at room temperature (RT) is 780 m/s and it decreases as the particle temperature increases. Certain process conditions resulted in improved coating properties as the temperature of the particles was affected by the process gas temperature and pressure. The mechanical properties such as the bond strength of the coatings formed under various process conditions were evaluated and compared. The relationships between the resulting properties, processing conditions, and the structures of the coatings are discussed.
Keywords
aluminum, cold spray, mechanical properties
1. Introduction In general, a Cu liner is used for shaped charge ammunition such as explosively formed penetrators (EFP) in military applications. The liner is accelerated by an explosion and subsequently experiences severe superplastic deformation at high strain rates (~1.0 9 105) (Ref 1, 2). Also, the penetration depth of the liner is directly affected by the density of the liner materials and the maximum length of the jet, which is a function of the jettip velocity (Ref 3, 4). Accordingly, in order to increase the penetration depth and destructiveness, other materials or combinations of materials have been used (Ref 3-5). When high density liner materials are used, the penetration depth increases and the destructiveness decreases (Ref 3, 4). Similarly, when reactive materials with a low density such as Al or Mg are used, the penetration depth Juyeon Won, Gyuyeol Bae, Kicheol Kang, and Changhee Lee, Kinetic Spray Coating Laboratory, Hanyang University, Seoul, Korea; See Jo Kim, Advanced Material Processing Laboratory, Andong National University, Andong, Korea; Kee-Ahn Lee, School of Advanced Materials Engineering, Andong National University, Andong, Korea; and Seong Lee, Agency for Defense Development, Daejeon, Korea. Contact e-mail: chlee@ hanyang.ac.kr.
818—Volume 23(5) June 2014
decreases and the destructiveness increases (Ref 5). Therefo
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