以包層Ti-15Cu-15Ni填料紅外線真空硬銲鈦合金

Abstract

使用銀基、鋁基及鈦基填料硬銲接合鈦合金曾經被廣泛的研究。根據先前的研究顯示，因為使用鈦基填料能得到與基材接近的機械性質與優越的抗腐蝕性，因此鈦基填料是硬銲鈦合金時最佳的選擇之一。使用Ti-15Cu-15Ni填料真空硬銲鈦合金的銲道顯微組織演化，主要與填料中溶質原子的重新分部有關，尤其是銅與鎳原子。在銲道中主要由三種相所構成：連續白色相、層狀白黑混合相以及在銲道與基材邊緣的針狀組織。對於低溫及短時間之真空鈦合金硬銲製程而言，使用合金包層之Ti-15Cu-15Ni填料可以得到較佳的銲道均勻性。儘管使用Wesgo Ticuni箔片時，需要花最多的時間來熔化未溶解的層狀填料，然而在高溫長時間之硬焊實驗中，可以得到最佳的焊道均勻性。另一方面，使用傳統的Ti-15Cu-15Ni填料硬銲時，會在銲道中出現大量連續白色的富銅鎳的介金屬相。銲道的均質化速率也會受鈦合金中合金元素的影響，在此次研究中，銅與鎳之擴散速率在Ti-15-3銲道最慢，而在Ti-6Al-4V中最快。

The brazing of Ti alloy using Al-, Ag- and Ti-base filler alloys has been extensively studied. Based on previous studies, the Ti-base braze alloy is considered as one of the best choices for the filler metal due to their high shear strength and superior corrosion resistance. The microstructural evolution of infrared vacuum Ti alloy brazed joint using Ti-15Cu-15Ni is primarily depended upon the redistribution of the solute atoms, especially Cu and Ni. Three distinguished phases in the brazed joints can be observed in most brazed joints including continuous white phases, layered white and dark eutectoid phase, and acicular phase. Better microstructural homogeneity of joint can be achieved by using alloy clad fillers for short time and/or low temperature condition. Brazing using Wesgo Ticuni foils took the longest time to dissolve all of the clad layers into the melt during the brazing cycles; however, the most homogeneous brazed joints can be obtained from using higher brazing temperature and/or time. On the contrary, a huge amount of continuous Cu and Ni-rich Ti phases appeared at the joint brazed using traditional Ti-15Cu-15Ni filler. Additionally, the homogenization rate of the brazed joint is also affected by the alloy elements in Ti base metal. Based on the experimental observations, it shows the depletion rate of both Cu and Ni atoms in the Ti-15-3 brazed joint was the lowest, and that in the Ti-6Al-4V substrate was the highest.