摘要
和基体厚度相比,涂层很薄,因此细观力学模型可把基体作为半无限弹性体。由于涂层和基体材料的膨胀系数及弹性系数不匹配,涂层材料中残余热应力的解析解为 E_c/(1-γ_c)·(α_s-α_c)△T。用有限元法校核,该应力和解析解吻合得好。通过对涂层产生裂纹驱动力和断裂韧性的讨论,提出了抗裂涂层厚度公式。
Usually the coating is very thin compared with substrate.The micro-mechanical modelwith semi-infinitely thick substrate is presented.The analytical solution of mismatch stress isE_c/(1-γ_c)·(α_s-α_c)△T.By using finite element method,the numerical solution of this stress agrees wellwith the analytical solution.The driving force and fracture resistance for cracks of coatings are discussed,and a formula for designing the thickness of coating is presented.
关键词
涂层
断裂韧性
材料力学
coating
substrate
semi-infinite elastic body
driving force
fracture toughness
