Uniaxial ratcheting behavior of anisotropic conductive adhesive film at elevated temperature

A series of uniaxial ratcheting experiments on anisotropic conductive adhesive films (ACFs) were conducted under stress-control at elevated temperature using DMA (DMA-Q800). The effects of mean stress, stress amplitude, applied temperature and loading history on the uniaxial ratcheting behavior of ACF were investigated. The results show that Young's modulus of the ACF declines rapidly with increasing temperature. The ratcheting strain increases as the mean stress, stress amplitude and temperature increased. Especially, when the temperature was over 80 degrees C, the ratcheting strain accumulated rapidly. There are significant differences in the uniaxial ratcheting behavior of ACF at 80 degrees C and 120 degrees C. The ratcheting strain rate at 120 degrees C is nearly twenty times that at 80 degrees C. The ratcheting strain decreases with increasing stress rate. Furthermore, the loading history also plays an important role in the progress of ratcheting. Previous cycling with higher stress amplitude greatly reduces ratcheting strain of subsequent cycling at lower stresses. (C) 2011 Elsevier Ltd. All rights reserved.