A novel diffusion model considering curvature radius at the bonding interface in a titanium/steel explosive clad plate

Abstract

This article introduces an element diffusion behavior model for a titanium/steel explosive clad plate characterized by a typical curved interface during the heat-treatment process. A series of heat-treatment experiments were conducted in the temperature range from 750°C to 950°C, and the effects of heat-treatment parameters on the microstructural evolution and diffusion behavior were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and electron-probe microanalysis. Carbon atoms within the steel matrix were observed to diffuse toward the titanium matrix and to aggregate at the bonding interface at 850°C or lower; in contrast, when the temperature exceeded 850°C, the mutual diffusion of Ti and Fe occurred, along with the diffusion of C atoms, resulting in the formation of Ti-Fe intermetallics (Fe 2 Ti/FeTi). The diffusion distances of C, Ti, and Fe atoms increased with increasing heating temperature and/or holding time. On the basis of this diffusion behavior, a novel diffusion model was proposed. This model considers the effects of various factors, including the curvature radius of the curved interface, the diffusion coefficient, the heating temperature, and the holding time. The experimental results show good agreement with the calculated values. The proposed model could clearly provide a general prediction of the elements' diffusion at both straight and curved interfaces.

Interface Characteristic of Explosive-Welded and Hot-Rolled TA1/X65 Bimetallic Plate

“…As shown in Figure 6b,c, there was no obvious diffusion region of Ti and Fe at the straight bonding interface, while a mono-peak of carbon element was observed at the place where the black layer existed (Figure 6b). Therefore, the so-called black layer was actually the result of the segregation phenomena of carbon element, and Jiang et al [47] also observed this phenomenon in their study. The vortex shown in Figure 6a formed due to the liquid metal jet in the front of the detonation wave propagation was intercepted during the explosive welding [48,49], where multiple elements such as Ti, Fe, C, and Mn were mixed and dissolved to produce various hard and brittle intermetallic compounds including FeTi, Fe2Ti and TiC [50,51], and cracks were easy to be formed in the vortex during the rolling process.…”

“…As shown in Figure 6b,c, there was no obvious diffusion region of Ti and Fe at the straight bonding interface, while a mono-peak of carbon element was observed at the place where the black layer existed (Figure 6b). Therefore, the so-called black layer was actually the result of the segregation phenomena of carbon element, and Jiang et al [47] also observed this phenomenon in their study.…”