銀基填料對高熵合金真空硬銲特性之研究

Abstract

摘要 高熵合金為近年國內自行開發出來的新材料，運用多種金屬元素共同組成，每種元素至多不超過35 %，經各種元素排列組合後，可組合成許多種新合金，較傳統合金更耐蝕、更耐高溫、硬度高且不易氧化。 本研究中以BAg-2及BAg-3二種銀基硬銲填料，於真空爐中進行高熵合金硬銲性能研究，研究結果顯示，FeCoNiCrCuAl0.5高熵合金鑄件為FCC相及微量的BCC相所組成，樹枝間相為富Cu的偏析相，經硬銲熱循環750℃持溫15分鐘熱處理後，BCC相之繞射強度明顯較鑄造態增強，顯示基地有更多之BCC相被析出。FeCoNi0.5CrAl0.5高熵合金鑄件結構由FCC相及BCC相所組成，主因為合金成份中缺少FCC相的促進元素Cu，與減半的Ni元素，故在凝固過程較易形成BCC相。以BAg-2銀基填料真空硬銲FeCoNiCrCuAl0.5及FeCoNi0.5CrAl0.5高熵合金，接合區域均無界面化合物產生；而以BAg-3銀基填料進行真空硬銲，高熵合金母材成份元素中Fe、Ni、Cr、Co在硬銲接合過程中熔入接合區域之交界處中。 關鍵字：高熵合金、硬銲、偏析相

ABSTRACT The development of high-entropy alloys has aroused considerable interest recently. These newly developed alloys have good corrosion and wear resistance , high temperature mechanical proerities , and special physical and chemical properties . The objective of this study was to investigate the properties of two high-entropy alloys , FeCoNiCuAl0.5 and FeCoNi0.5CrAl0.5 , and their brazing ability with filler metals BAg-2 and BAg-3 . The vacuum brazing process was used .Optical metallography and SEM+EDAX analysis were conducted to investigate the microstructure analysis and element distribution . The results of this study shown as follows: The microstructure of FeCoNiCuAl0.5 high entropy alloy casting showed that the matrix consists of a FCC phase with a small amount of BCC phase on it, and the interdendritic segregation was specified as a copper rich phase. The microstructure of FeCoNi0.5CrAl0.5 high entropy alloy consisted of FCC phase and BCC phase. Using silver based BAg-2 as a vacuum hard solder for FeCoNiCrCuAl0.5 and FeCoNi0.5CrAl0.5 high entropy alloys, no interface compound formed at joint area. However, when using BAg-3 as the hard solder, it was found that the constituent elements of the matrix, such as Fe, Ni, Cr and Co dissolved into the interface during the joint process.