銀基填料(Ag-Cu-Ti)與Ti-6Al-4V之真空硬銲接合研究

鈦合金具有強度重量比高、疲勞強度及抗腐蝕能力佳等優點。因此在飛機、航太及醫療等領域有很多的應用。真空硬銲因為具有不需要使用助銲劑、銲後工件外表美觀等優點，因此特別適用於銲接工件會與保護氣氛產生不良反應，或銲道內不允許殘留助銲劑之情況。因為真空硬銲具有這些特性，它在航太、核子以及電子領域應用很多。但是要以階層實驗方法獲得真空硬銲最佳參數，不但費時，成本也高。本研究運用真空硬銲製程以及銀銅鈦合金(Ag68.8,Cu-26.7,Ti-4.5)填料，進行鈦合金(Ti-6A1-4V)接合。為了減少尋找最佳參數組合(硬銲溫度、接合間隙、加熱過程、表面粗糙度、搭接長度)所需的實驗次數，本研究採用田口直交法。另外，為了精確控制硬銲試片的接合間隙及搭接長度，本研究設計一組特別的組合夾具。本研究發現硬銲溫度、加熱過程、接合間隙、表面粗糙度對於銲道的機械強度有顯著的影響。硬銲溫度880℃、持溫10分鐘、接合間隙0.05mm、表面粗糙度Ra0.3μm的參數組合，可達成最佳的銲道強度。

關鍵字

真空硬銲,Ti-6Al-4V,銀基填料

並列摘要

Titanium alloys are excellent in strength-to-weight ratio, fatigue strength and corrosion resistance. These characters make them ideal for varied applications in aircraft, aerospace, and medical fields. Vacuum brazing needn't flux, so it's particularly well suited for joining parts which reacts adversely with other atmospheres or when entrapped fluxes or gases would be intolerable. Therefore, it has found wide application in the aerospace, nuclear and electronic fields. Nevertheless, to obtain the optimum vacuum brazing process variables by factorial experiments is time and cost consuming. This study applies vacuum brazing and silver-copper-titanium alloy (Ag-68.8, Cu-26.7, Ti-4.5) filler metal to join titanium alloy(T1-6A1-4V). And, in order to reduce the number of factorial experiments in finding the optimum vacuum brazing process variables combination (brazing temperature, join clearance, heating profile, surface roughness, overlap distance), the orthogonal array of Taguchi methods is adopted. A particular assembling fixture is designed to precisely control the join clearance and overlap distance of test specimens. In this study, it is found that control factors of brazing temperature, heating profile, joint clearance, and surface roughness have significant effects on the mechanical strength of a brazed joint. And, the combination of brazing temperature 880℃, holding time 10 minutes, joint clearance 0.05mm, surface roughess Ra0.3μm is optimal for maximum joint strength.