本研究探討新型熱塑性中間層輔助無攪拌針摩擦攪拌點焊（probeless friction stir spot welding， P-FSSW）應用於 AA6061 鋁合金與熱固性碳纖維強化高分子複合材料（carbon fiber-reinforced polymer， CFRP）異材接合之界面接合特性。由於熱固性 CFRP 之樹脂基材於固化後無法再次熔融與流動，直接進行無攪拌針摩擦攪拌點焊時，界面貼合性及載荷傳遞能力有限。為改善上述問題，本研究於 AA6061 鋁合金與熱固性 CFRP 之間導入厚度 0.3 mm 之聚醯胺 6（polyamide 6， PA6）熱塑性中間層，並進一步比較未預接合、結構膠預接合、雷射預接合，以及不同插入深度對接頭性能之影響。 結果顯示，未導入中間層之直接接合試片，其平均最大載荷及剪切強度分別僅為 0.27 kN 與 3.31 MPa，顯示 AA6061 與熱固性 CFRP 之直接界面接合能力不足。導入 PA6 熱塑性中間層後，平均最大載荷及剪切強度分別提升至 1.36 kN 與 17.19 MPa，顯示 PA6 可改善界面填充狀態，並提供額外之載荷傳遞與輔助承載效果。進一步採用預接合處理後，接頭性能可再獲得提升；其中，結構膠預接合及雷射預接合試片之剪切強度分別達 27.13 MPa 與 31.97 MPa，相較於僅導入 PA6 中間層之接頭，分別提升 57.8% 與 86.0%。 在雷射預接合條件下，當轉速為 2000 rpm、下壓速率為 3 mm/min、插入深度為 0.3 mm，且停留時間為 7 s 時，可獲得最佳接頭性能，其平均最大載荷及剪切強度分別為 2.51 kN 與 31.97 MPa。然而，當插入深度增加至 0.6 mm 時，因 PA6 中間層受到過度擠壓而產生變薄、擠出及局部間隙，使接頭性能下降。 綜合而言，PA6 熱塑性中間層結合雷射預接合處理可有效提升 AA6061 與熱固性 CFRP 之初始界面貼合性，促進摩擦攪拌過程中的高分子填充，並有助於形成微機械嵌合。本研究結果顯示，藉由新型熱塑性中間層與雷射預接合之結合，可提升 AA6061 鋁合金與熱固性 CFRP 異材接頭之承載性能與界面接合穩定性。;This study investigates the dissimilar joining of AA6061 aluminum alloy and thermosetting carbon fiber-reinforced polymer (CFRP) using probeless friction stir spot welding (P-FSSW). Because the cured thermosetting CFRP matrix cannot be remelted or plastically flowed during welding， direct joining provides limited interfacial conformity and load-bearing capacity. A 0.3 mm-thick polyamide 6 (PA6) thermoplastic interlayer was therefore introduced to improve joint formation and load transfer. Five joint configurations were investigated， including direct P-FSSW， PA6-interlayer-assisted P-FSSW， adhesive pre-bonded PA6-interlayer P-FSSW， laser pre-bonded PA6-interlayer P-FSSW， and a laser pre-bonded condition processed with a larger plunge depth of 0.6 mm.
Direct P-FSSW exhibited an average maximum load of 0.27 kN and a shear strength of 3.31 MPa， indicating insufficient load transfer across the AA6061/CFRP interface. Incorporation of the PA6 interlayer increased the average maximum load and shear strength to 1.36 kN and 17.19 MPa， respectively， owing to improved interfacial filling and interlayer-assisted load transfer. Pre-bonding further improved the joint performance. Adhesive and laser pre-bonding increased the shear strength to 27.13 and 31.97 MPa， corresponding to improvements of 57.8% and 86.0%， respectively， compared with the PA6-interlayer condition. The highest performance was obtained using laser pre-bonding at 2000 rpm， a plunge rate of 3 mm/min， a plunge depth of 0.3 mm， and a dwell time of 7 s， achieving an average maximum load of 2.51 kN and a shear strength of 31.97 MPa. A larger plunge depth of 0.6 mm reduced joint performance because of excessive PA6 thinning， extrusion， and local gap formation.
The combined PA6 interlayer and laser pre-bonding approach improved initial interfacial conformity， facilitated polymer filling during P-FSSW， and promoted micro-mechanical interlocking. These findings provide an effective route for improving the load-bearing performance of AA6061/thermosetting CFRP hybrid joints.
