填料及Fiber Laser參數對Al-Cu異質金屬銲件機械性質及介金屬特性影響之分析

Effect of fillers and Fiber Laser welding parameters on the mechanical properties and intermetallic compound formation of the Al-Cu dissimilar metals weldment

黃柏皓(Po-Hao Huang)

指導教授 ： 陳厚光

共同指導教授 ： 王惠森(Huei-Sen Wang)

義守大學/理工學院/材料科學與工程學系/碩士(2021年)

摘要

為了提供鋁(Al)-銅(Cu)銲接件有高強度之機械性質，本研究採用高速掃描Fiber Laser(快速給予高能量且冷卻速率較快)搭配不同的銲接參數(例如:雷射功率與銲接速度)及填料(Filler,例如:4032 Al-Si合金、Sn箔)以疊銲的方式進行銲接，並於銲接後對銲接件的機械性質與微組織進行測試及綜合分析，進而了解銲接參數與填料差異對Al-Cu銲接件介面之介金屬化合物(Intermetallic Compounds, IMCs)分布及對銲接件機械性質之影響。
實驗結果顯示，隨著銲接功率增加，銲道熔融區深度及面積越大，其最大拉伸荷重也有上升的趨勢，且在銲道未穿透的條件下，以參數Q(Al上Cu下添加Sn箔、功率2.5 kW)的搭疊方式具有最大的拉伸荷重(789.7 N)；參數K(Cu上Al下無填料、功率2.0 kW)的搭疊方式有最高延展性，伸長量為0.95 mm)。從銲後微組織綜合分析結果可以得知Al-Cu IMCs大致上分為黑區(Al(Cu)，平均Cu含量6.57 at%)、灰區(Al(Cu)、θ-CuAl2之兩相區，平均Cu含量16.08 at%)、Dendritic(θ-CuAl2，平均Cu含量32.68 at%)區、塊狀結構(η2-CuAl，平均Cu含量49.60 at%)、富Cu IMC(γ1-Cu9Al4，平均Cu含量66.48 at%)；而添加Sn箔後可以定義出新的IMCs為富Sn區、α(Cu)+ε-Cu3Sn及白色絲狀組織或網狀結構(γ1-Cu9Al4、η-Cu6Sn5及β-Sn組成三相區)。由機械性質結果可以發現塊狀結構、富Cu IMC、白色絲狀組織或網狀結構為低破裂性質之硬脆相結構；且可以從拉伸破斷面得知Al上Cu下添加Sn箔後銲道有變寬的現象及銲道中間由θ-CuAl2、η2-CuAl、γ1-Cu9Al4所包覆著，故拉伸荷重為最高；而Cu上Al下銲道中間由連續分布θ-CuAl2所包覆，能承受拉伸變形量較大，故延展性較好。

關鍵字

填料 ； 雷射銲接 ； 微組織 ； 機械性質 ； 介金屬化合物

並列摘要

To provide the better mechanical properties of the welding joint, this study uses a high speed scanning Fiber Laser technique with various welding parameters (e.g. welding power and speed) and fillers (e.g. 4032 Al-Si alloy and Sn foil) to overlap weld the Al-Cu pieces. After welding, the microstructure evolution and mechanical properties of the welds are investigated and analyzed. From the test results, the formation mechanism of the intermetallic compounds (IMCs) and the effects on weld properties caused by the variation of the welding parameters and fillers are defined.
The results showed that, with the increase of welding power, the depth and area of the weld fusion zone (WFZ) increase resulting the increase of the tensile loads. If the WFZ is not penetrated, the welding condition Q (lap welding method with Al on top and Cu on bottom, with Sn foil, peak power is 2.5 kW) has the highest tensile load (789.7 N); the welding condition K (lap welding method with Cu on top and Al on bottom, with no filler, peak power is 2.0 kW) has the highest ductility (elongation is 0.95 mm). From analysis results of the microstructure after welding, it is observed that Al-Cu IMCs are roughly divided into many areas, including: black area (Al(Cu), the average Cu content is 6.57 at%), grey area (Al(Cu) and θ-CuAl2, a two-phase area, the average Cu content is 16.08 at%), Dendritic (θ-CuAl2, average Cu content is 32.68 at%) area, lump structure (η2-CuAl, average Cu content is 49.60 at%), Cu-rich IMC (γ1-Cu9Al4, average Cu content is 66.48 at%).
By adding Sn foil filler, new extra IMCs can be found, such as: Sn-rich area, α(Cu)+ε-Cu3Sn and white network structures (γ1-Cu9Al4, η-Cu6Sn5 and β-Sn form a three-phase zone). From the results of microhardness test, it is found that the lump structure, Cu-rich IMC, white network structures are hard and brittle phases; Furthermore, from the tensile fracture surface, lap welding method with Al on top and Cu on bottom and with Sn foil tends to produce a wider WFZ. Also, the centre of the WFZ is mainly composed by θ-CuAl2, η2-CuAl and γ1-Cu9Al4, resulting in a higher tensile load; for the lap welding method with Cu on top and Al on bottom and with no filler, the center of the WFZ is mainly composed by the continuous θ-CuAl2 phase, which can withstand the larger tensile deformation and provide the better ductility.

並列關鍵字

Al-Cu ； Filler ； Laser welding ； Microstructure ； Mechanical properties ； Intermetallic compounds

參考文獻

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