The Study of Brazing Two Metallic Substrates Using Ni-Based Fillers

本實驗先以兩種含B的鎳基填料，真空硬銲接合Inconel 600母材。接合界面經由顯微組織分析可知，當硬銲製程參數改變，能使銲道中心與接合處附近的析出物數量與形態發生改變。提高硬銲溫度與增加持溫時間，會使填料内的B原子藉由擴散進入母材，相對在銲道內的BCr析出物尺寸變小或消失，但相對的在接合處附近，因為B原子擴散進入母材與母材的Cr原子在晶界或者在晶粒上形成連續或顆粒狀的B-Cr化合物，即使最高硬銲溫度與持溫時間的參數，仍然無法有效消除在晶界上的連續狀B-Cr化合物。此外，研究中亦以316不鏽鋼為母材的進行硬銲接合研究，實驗結果發現，在銲道中心會析出BCr2的顆粒狀介金屬化合物，而接合處附近往母材内部，會在晶界上大量連續析出BCrFe三元析出物，當提高硬銲溫度與增加持溫時間時，銲道內的BCr2析出量減少或消失，填料的B原子由晶界擴散進入母材內部，與母材的Fe原子與Cr原子形成BCrFe三元析出物，且隨著硬銲溫度與持溫時間增加時，BCrFe三元析出物變成不連續析出物。First, the brazing of Inconel 600 using two boron-containing nickel-based fillers has been extensively studied. Based on SEM microstructural and WDS chemical analysis results, the mount and shape of precipitates in the central weld and bonding interface will change with brazing parameters. With increasing brazing temperature and brazing timed diffusion of boron into the base metal, result in decreasing amount of BCr and BCr2 intermetallic compounds in the weld and both continuous as well as granular B-Cr intermetallic compounds formal along grain boundaries. Even the maximum brazing temperature or brazing time are not able to effectively eliminate continuous precipitates along grain bundaries. The next study is brazing 316 stainless steel. According to the experimental results, BCr2 intermetallic conpound is formed in the weld and BCrFe ternary intermetallic phase is observed along grain boundaries at low brazing temperature or time. The brazing joint is primarily consist of Ni/Cr/Fe-rich and BCr2 intermetallic phase. The amount of BCr2 intermetallic compound is decreased in the centeral of weld with increasing brazing temperature and time. Boron content in the filler metal diffuses from weld to the base metal and forms BCrFe ternary intermetallic compound