High Temperature Deformation Behavior of In-Situ Synthesized Titanium-Based Composite Reinforced with Ultra-Fine TiB Whiskers

Abstract

A TiB/Ti-6Al-4V composite reinforced with ultra-fine TiB whiskers (UF-TiB) was prepared by the powder metallurgy method. High temperature compression tests were carried out to study the hot deformation behavior of the UF-TiB/Ti-6Al-4V composite. The compressive deformation was performed in the temperature range of 900–1200 °C and the strain rate range of 0.001–10 s−1. The results showed that stable flow occurred at the condition of 900–1200 °C/0.001–0.01 s−1. The optimum working condition was 900 °C/0.001 s−1, with the deformation mechanism of dynamic recrystallization (DRX). Instable flow occurred when the strain rate was higher than 0.01 s−1, where the failure modes included adiabatic shear deformation, whisker breakage and whisker/matrix debonding. The deformability of the UF-TiB/Ti-6Al-4V composite was much better than the traditional casted and the pressed + sintered TiB/Ti-6Al-4V composites, which are typically reinforced with coarse-grained TiB whiskers. The high deformability was primarily attributed to the ultra-fine reinforcements, which could coordinate the deformation more effectively. In addition, a fine matrix microstructure also had a positive effect on deformability because the fine matrix microstructure could improve the grain boundary sliding.

Effect of Graphene Nanosheets Content on Microstructure and Mechanical Properties of Titanium Matrix Composite Produced by Cold Pressing and Sintering

“…A large number of TMCs have been produced with ceramic reinforcements, such as TiB [7], Al 2 O 3 [8], TiN [9], SiC [10], and TiC [11]. Although these reinforcements improve the mechanical properties and have suitable compatibility, their densities are higher than that of titanium [12].…”

Effects of substrate heating on the microstructure and hardness of TiB/Ti6Al4V-ELI during laser in-situ metal deposition

“…Based on the observation made by Xu et al ( 2018) after XRD analysis, the white, grey and dark phases can be identified as α, β, and TiB whiskers, respectively. Since Ti6Al4V-ELI is α + β alloy, the presence of these two phases after deposition was expected and is supported by the finding of Xu et al (2018). Furthermore, since pre-heating was used to control the cooling rate, the presence of these two phases were expected without the formation of martensite α. Preheating at 200°C led to the formation of two types TiB whiskers with different morphologies as can be seen in Figure 3(b).…”

“…These defects typically lead to premature part failure. 17,22,24,25 A method to cure residual stresses during manufacturing and overcome these occurrences is to perform continuous base plate heating during material deposition. According to literature, base plate heating reduces thermal gradients within the built part, which improve the microstructure and result in minimal or complete elimination of residual stresses.…”

Effects of Melt Hydrogenation on the Microstructure Evolution and Hot Deformation Behavior of TiBw/Ti-6Al-4V Composites

“…Therefore, interest in in situ TiBw-reinforced Ti-6Al-4V composites has been growing over the past few years. Several processing techniques for the in situ synthesis of TiBw-reinforced titanium matrix composites have been developed, including powder metallurgy (PM) [ 13 ], spark plasma sintering (SPS) [ 14 ], self-propagating high-temperature synthesis (SHS) [ 15 ], selective laser melting (SLM) [ 16 ], and ingot metallurgy (IM) [ 17 ]. Due to the advantages of microstructure control and near net shape machining, these powder-based manufacturing technologies can produce customized products in industry sectors, but the expensive powder costs and lengthy process flow cannot meet the production demand of large size, heavy weight, and large-scale parts [ 18 ].…”