کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1571322 | 1514414 | 2012 | 10 صفحه PDF | دانلود رایگان |
Cracking in an electron beam weld of titanium to stainless steel occurred during the cooling process because of internal thermal stress. Using a copper filler metal, a crack free joint was obtained, which had a tensile strength of 310 MPa. To determine the reasons for cracking in the Ti/Fe joint and the function of the copper filler metal on the improvement of the cracking resistance of the Ti/Cu/Fe joint, the microstructures of the joints were studied by optical microscopy, scanning electron microscopy and X-ray diffraction. The cracking susceptibilities of the joints were evaluated with microhardness tests on the cross-sections. In addition, microindentation tests were used to compare the brittleness of the intermetallics in the welds. The results showed that the Ti/Fe joint was characterized by continuously distributed brittle intermetallics such as TiFe and TiFe(Cr)2 with high hardness (~ 1200 HV). For the Ti/Cu/Fe joint, most of the weld consisted of a soft solid solution of copper with dispersed TiFe intermetallics. The transition region between the weld and the titanium alloy was made up of a relatively soft Ti–Cu intermetallic layer with a lower hardness (~ 500 HV). The formation of soft phases reduced the cracking susceptibility of the joint.
► Electron beam welded Ti/Fe joint cracked for the brittleness and residual stress.
► Electron beam welded Ti/Cu/Fe joint with tensile strength of 310 MPa was obtained.
► Cu diluted Ti and Fe contents in weld and separated the TiFe2 into individual blocks.
► Interfacial hard Ti–Fe compounds were replaced by soft Ti–Cu compounds in the weld.
► A large amount of solid solution of copper formed in the weld.
Journal: Materials Characterization - Volume 73, November 2012, Pages 104–113