Three dimensional fiber orientation in vibration welded joints of glass fiber reinforced polyamide-6

摘要

A technique to obtain fiber orientation distribution was developed for the vibration-welded joints of polyamide-6 with 30% glass fiber. The heat affected zone (HAZ) of fiber reinforced polyamide-6 was successfully revealed by polishing and etching the HAZ. Under the polarized microscope in reflected light, detailed microstructure domains including bulk crystal zone and HAZ were observed. To obtain quantitative measurement of three dimensional fiber orientation distribution, orientation tensors were calculated from elliptical fiber cross section images. The fibers in HAZ were highly oriented toward the squeeze flow direction compared to the bulk phase. Thicker HAZ does not guarantee more random fiber orientation by average but higher fiber population more randomly oriented. High weld pressure at low amplitude promotes fiber reorientation in the tensile direction and thus weld strength.