The Microstructure of Diffusion-bonded Ti/Ni Interface

Interface Microstructure and Strength Properties of the Diffusion-Bonded Joints of Titanium ∣Cu Interlayer ∣ Stainless Steel

“…At 900°C for 150 minutes, the microvoids have been observed at the SS-Cu interface (Figure 3(a)) due to the imbalance in mass transfer across the interfaces and generate voids. Orhan et al [14] and Hinotani et al [15] reported a similar type of voids for the diffusion couple of microduplex stainless steel/titanium alloy and titanium/nickel, respectively. In the present work, in SEM-BSE images, these discontinuities are not clearly evident at the lower processing parameters due to their finer size.…”

Effects of Intermetallic Phases on the Bond Strength of Diffusion-Bonded Joints between Titanium and 304 Stainless Steel Using Nickel Interlayer

“…Orhan et al and Hinotani et al observed this kind of voids for the diffusion couple of microduplex SS-Ti alloy and Ti-Ni, respectively. [18,24] In the present work, in SEM-BSE, these discontinuities are clearly evident at processing temperatures of 900°C and above. At 900°C processing temperatures, these voids are very fine and their growth increases with the increase in the bonding temperature up to 950°C.…”

“…[11] The intrinsic diffusion coefficiency of Ti (D Ti = 5.5 · 10 -14 m 2 s -1 at 900°C and D Ti = 9 · 10 -14 m 2 s -1 at 800°C) is greater than a-Fe (D a-Fe = 5 · 10 -15 m 2 s -1 at 900°C), c-Fe (D c-Fe = 3 · 10 -17 m 2 s -1 at 900°C) and Ni (D Ni = 3 · 10 -17 m 2 s -1 at 800°C). [12,13,18] So, Ti diffusion becomes faster than iron and Ni, which produces the imbalance in flux flow across the interfaces and generates voids. At higher bonding temperature, the volume fraction of voids will be greater; hence, the discontinuities after 850°C processing temperature presumably play a vital role in lowering the bond strength.…”

“…[15,16] The Ni-Ti binary phase diagram shows the formation of various types of Ni-Ti base intermetallic. [17,18] In the present study, efforts were made to produce diffusion bonds of Ti and SS using Ni as an interlayer. The processing temperature was varied to obtain a good combination of strength and ductility of diffusion bond.…”

Influence of Bonding Temperature on Structure and Strength Properties of Titanium and Micro-duplex Stainless Steel Diffusion Bonded Joints

“…Hinotani et al and Orhan et al reports that the presence of such voids also occur for the diffusion couples of titanium-nickel and microduplex stainless steel-titanium alloy when processing was done at 700-800°C and 800°C, respectively. 12 ) at 900°C. The presence of voids produced by the kirkendall effect has been reported for diffusion bonded Ti-Ni couple.…”