樹脂－金属接合射出成形品の X 線 CT 画像解析による接合状態評価と接合強さの関係

(第二報) : 金属プレートの凹凸構造が接合強さに及ぼす影響

抄録

In this study, we investigated the effects of depth of uneven structure on joining strength at the joint between an aluminum plate with uneven structure and resin in resin-metal joined injection molding. It was confirmed that the shear joining strength increased and its variation decreased as the depth of the uneven structure increased. To elucidate the cause, we performed quantitative analysis of the resin filling state in the uneven structure using X-ray micro-CT observation and 3 D image analysis. As a result, it was confirmed that there was local peeling at the top of the boundary surface in the case of shallow unevenness. While for shear fracture samples, it was confirmed that the amount of the residual resin in the uneven structure of the metal side increased as the depth of the uneven structure increased. We also confirmed that the volume of the undercut-region inside the uneven area, and the volume of resin injected into the undercut-region, increased as the depth of the uneven structure increased. From the above, we speculate that as the depth of the uneven structure increases, the anchor effect at the joint becomes stronger, leading the fracture mode at the joint to change from peeling of the joining interface to destruction of the resin side. And we think that this leads to increased shear joining strength and decreased variation.