Relationship between microwave irradiation and constituents of composites during joining process

Two important things to be studied in the joining of thermoplastic composite materials using microwave irradiation are the relationship between the microwave energy and the matrix of the composite as well as that between the reinforcing fibre filaments and microwave irradiation. The characteristics of the thermoplastic matrix of the composite, eg structure, crystallinity, glass transition and heat-distortion temperatures are related to the heat transfer in the material during joining process. Microscopy study is used to find out the microstructural characteristics along and around the bondline of the welds. The separation distance of the reinforcing carbon filaments was varied and heat transfer in the material during joining was studied. The reasons why the thermoplastic matrix composite materials were weakened by prolonged microwave irradiation were also studied and analysed.