紅外線硬銲接合Ti50Ni50形狀記憶合金與Incoloy 800合金/Inconel 600合金之研究

Abstract

本研究使用Cu作為擴散阻絕層之三層填料(BAg-8/Cu/Cusil-ABA) 紅外線硬銲異質接合Ti50Ni50與Incoloy 800合金/Inconel 600合金/316L 不鏽鋼，以及使用金基填料AuPdNi紅外線硬銲異質接合Ti50Ni50與Inconel 600合金，探討在不同的參數下填料對基材之潤濕行為、顯微組織演化、銲點剪應力強度及破壞模式等。接合Ti50Ni50/Cusil-ABA/Cu/BAg-8/Incoloy 800時，銅箔厚度能大於50μm，銲道是由(CuxNi1-x)2Ti、Cu-rich、純Cu以及Ag-Cu共晶組織所組成；當銅箔厚度為50μm時，最佳條件在850℃×3min，剪應力強度有271MPa，破壞位置於Ag-Cu共晶組織與Incoloy 800的交界處，屬於延脆混合性破壞；當銅箔厚度為70μm時，在850℃×5min下，其剪應力強度為181MPa，亦為延脆混合性破壞；但當銅箔厚度為25μm時，銅箔失去了阻絕能力，Ti-Fe介金屬相生成，銲道由(CuxNi1-x)2Ti、Cu-rich、Ag-Cu共晶組織、Ti(Fe,Ni)以及TiFe2所組成，其剪應力強度最佳為222MPa。接合Ti50Ni50/Cusil-ABA/Cu/BAg-8/Inconel 600時，銲道由(CuxNi1-x)2Ti、Cu-rich、純Cu、(Ni,Cu)固溶體以及Ag-Cu共晶組織所組成，最佳條件在820℃×5min，剪應力強度有374MPa，破壞位置於Ti50Ni50/Cusil-ABA端之Ag-Cu共晶組織內，屬於延性破壞。AuPdNi可有效潤溼Inconel 600合金；接合Ti50Ni50/AuPdNi/Inconel 600時，銲道由TiNi3與TiNiAu(I)之層狀組織、TiNiAu(II)以及AuPdNi組成，在1050℃×5min下有最佳剪應力強度527MPa，破壞發生於TiNi3與TiNiAu(I)之層狀組織內部，為脆性破壞。接合Ti50Ni50/Cusil-ABA/Cu/BAg-8/316L 不鏽鋼時，銅箔為50μm時，銲道由(CuxNi1-x)2Ti、Cu-rich、Cu以及Ag-Cu共晶組織所組成，剪應力強度為354 MPa，屬延脆混合性破壞；銅箔為25μm時，316L端生成Ti-Fe介金屬相，剪應力強度為140MPa，為脆性破壞。

BAg-8, Cusil-ABA, Copper, and Au-22Ni-8Pd fillers are used to infrared braze Ti50Ni50 and three other alloys, Incoloy(IY) 800, Inconel(IN) 600 and 316L stainless steel(SS). The brazed joint’s interfacial reaction, microstructure evolution and shear strength are investigated. Cu film is used as a diffusion barrier in the three-layer filler to become a TiNi/Cusil-ABA/Cu/BAg-8/IY 800 joint to prevent the formation of brittle intermetallics in the joint, which composes of (CuxNi1-x)2Ti, Cu-rich, Cu, and Ag-Cu eutectic. When Cu film thickness is 50μm, the shear strength is 271MPa for the joint brazed at 850℃×3min, but when its thickness increases to 70μm, the joint’s shear strength reaches 181 MPa due to its thickness is over. However, when its thickness is reduced to 25μm, it cannot prevent the formation of brittle Ti-Fe intermetallics and the shear strength reduces to 222 MPa. For joining TiNi and IN 600 using AuPdNi filler, a lamellar sturctuer of TiNi3 and Ti-Ni-Au(I), and a layer of Ti-Ni-Au(II) can be observed at TiNi side, and solid solution of AuPdNi and that of (Au,Ni) can be observed at IN600 side. The shear strength can reach 527 MPa when it is brazed at 1050℃×5min. For TiNi/Cusil-ABA/50μm Cu/BAg-8/IN 600 joint, it is also composed of (CuxNi1-x)2Ti, Cu-rich, Cu, and Ag-Cu eutectic, and has the shear strength of 374MPa for brazing at 820℃×5min. For TiNi/Cusil-ABA/Cu/BAg-8/316L SS joint, it is composed of (CuxNi1-x)2Ti, Cu-rich, Cu, and Ag-Cu eutectic and is similar to those of barzing TiNi/Cusil-ABA/Cu/BAg-8/IY 800 joint with a Cu diffusion barrier. The shear strength of this joint using 50μm Cu film is 354MPa brazed at 820℃×5min. When the thickness of Cu film reduced to 25μm, Ti-Fe brittle intermetallics appear at 316L SS side, and the shear strength is reduced to 140 MPa at 820℃×5min.