THE QUENCHING STRESS IN THERMALLY SPRAYED COATINGS
THE QUENCHING STRESS IN THERMALLY SPRAYED COATINGS
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DOI：
10.1016/0040-6090(91)90029-w
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发表时间：
1991-05-01
期刊：
影响因子：
2.1
通讯作者：
CLYNE, TW
中科院分区：
文献类型：
--
作者：
KURODA, S;CLYNE, TW
研究了影响等离子喷涂沉积物中残余应力的各种材料特性。 在涂层厚度远小于基体厚度的情况下，给出了等离子喷涂涂层残余应力的简单表达式。 该方程包含两项，即由于喷射板的淬火引起的应力和由不均匀热收缩引起的宏观热应力。 对方程中的变量进行了实验研究，描述了测量淬火应力的方法，并给出了各种材料和沉积条件下的淬火应力值。 对于金属粉末，可以在淬火应力的大小与材料经历蠕变变形和/或塑性屈服的倾向之间建立相关性。 对于陶瓷粉末如Al 2 O3，这是不可能的，并且淬火应力非常低。 机制建议减少淬火应力，微裂纹是一个突出的建议。 飞溅之间的不良结合和小的解体颗粒的结合也可能是significant.Mechanical和热性能的喷涂材料，如杨氏模量和热膨胀系数，已被测量。 孔隙度的影响进行了检查，使用Eshelby等效均匀夹杂物的方法。 强调了在定量建模工作中使用现场测量特性的重要性。
Various material properties which influence residual stresses in plasma-sprayed deposits are examined. A simple expression to evaluate the residual stress in a plasma-sprayed coating is given for the case where the coating thickness is much smaller than the substrate thickness. The equation contains two terms, the stress owing to quenching of sprayed splats and the macroscopic thermal stress arising from differential thermal contraction. The variables in the equation have been studied experimentally.Methods of measuring the quenching stress are described and values are reported for a wide range of materials and deposition conditions. For metallic powders, correlation can be established between the magnitude of the quenching stress and the propensity of the material to undergo creep deformation and/or plastic yielding. For a ceramic powder such as Al2O3 this is not possible and the quenching stress is very low. Mechanisms are suggested for the reduction in the quenching stress, microcracking being a prominent suggestion. Poor bonding between splats and the incorporation of small disintegrated particles are probably also of significance.Mechanical and thermal properties of sprayed materials, such as Young's modulus and the coefficient of thermal expansion, have been measured. Effects of porosity are examined using the Eshelby equivalent homogeneous inclusion method. The importance of using measured in situ properties in quantitative modelling work is emphasized.