Acoustic approach of weldability for nanocomposite (nanosilica/PA6) welded by ultrasonic welding

Abstract Polymer matrix nanocomposites (NMP) have attracted a great interest mainly in the automotive, aerospace and medical industries since they have good mechanical properties, dimensional, thermal and chemical stability, as well as interesting electrical conductivity and cost reduction in the manufacturing process. However, welding of this class of materials presents serious challenges such as improving weldability of the joint and understanding the mechanisms responsible for coalescence. The objective of this work was to evaluate the coalescence of an NMP joint (comprising a PA6 matrix and with nanosilica of different percentages of silicon) using ultrasonic welding, as well as to perform an acoustic approach of the energy dissipation during the welding process. It is concluded that the NMP samples tend to show better coalescence as the percentage of nanosilica increases, up to a certain limit. On the other hand, the higher the content of nanoparticle the smaller the energy absorption.

摘要 聚合物基纳米复合材料（Polymer matrix nanocomposites, NMP）凭借优异的力学性能、尺寸稳定性、热稳定性与化学稳定性，同时兼具良好的导电性能且可降低制备工艺成本，故而在汽车、航空航天及医疗行业备受青睐。然而，此类材料的焊接仍面临诸多严峻挑战，例如优化接头的可焊性以及阐明接头熔合的内在作用机制。本研究旨在通过超声波焊接技术，评估以聚酰胺6（PA6）为基体、掺杂不同比例纳米二氧化硅的NMP接头的熔合性能，并对焊接过程中的能量耗散开展声学分析。研究结果表明，随着纳米二氧化硅添加比例的提升，NMP试样的接头熔合效果逐步优化，直至达到某一临界阈值；另一方面，纳米颗粒含量越高，材料的能量吸收能力越低。