Effect of Heat Treatment on Creep Properties of in situ Synthesized (TiB+La2O3)/Ti Composite

Abstract

TiB+La 2 O 3)/IMI834 titanium matrix composites (TMCs) were developed by in situ synthesized in a consumable vacuum arc-remelting furnace. A new TRIPLEX treatment and β heat treatment were developed in this study. The effect of heat treatment on microstructure, tensile properties and creep rupture behavior of in situ synthesized (TiB+La 2 O 3)/IMI834 titanium matrix composites (TMCs) and corresponding matrix alloy were investigated. The results show that widmanstätten and lamellar α structure formed after the new TRIPLEX heat treatment procedures. Compared with traditional β heat treatment, the creep strain rate increases slightly, but the elongation increases significantly (increase 126% at 293 K, 59.13% at 873 K). The fracture mechanism is attributed to the broken of TiB whiskers after bearing high stress. The creep fracture mechanism is due to the load transfer of TiB whiskers and interfacial debonding. The Creep strain rates of TMCs are lower than that of matrix alloy, which is attribute to that loading of TiB and the pinning effect of finer La 2 O 3 particles on dislocation movement.

Effect of heat treatment on microstructure, mechanical and tribological properties of in-situ (TiC+TiB)/TC4 composites by casting

“…Compared with the conventional solution of HT1, the HT2 heat treatment undergoes a second stage of solution in the α+β region. This double high-temperature solution causes the α phase to continuously grow, resulting in an increase of the length-diameter ratio of the α grain [46,47] . The content and size of the α phase during the TRIPLEX heat treatment process depend mainly on the solution temperature of the first and second stages.…”

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

“…However, the as-cast ingots always have many defects and low mechanical properties due to the inhomogeneous microstructure. To eliminate casting defects, refine grains, and improve mechanical properties, TMCs ingots usually need multiple steps of thermo-treatment and solid deformation [ 19 , 20 ]. In addition, the reinforcements could be easily broken in these post-processes, and the interface between hard ceramic particles and soft matrix alloy will be prone to crack due to the stress concentration.…”

Microstructure and Mechanical Properties of Lab6/Ti-6al-4v Composites Fabricated by Selective Laser Melting

“…Most of the previous studies have prepared Ti-based composites reinforced with TiB and the rare earth oxide La2O3 via in-situ reactions between Ti and LaB6. Li et al [9] prepared TiB+La2O3 reinforced titanium matrix composites by vacuum electric arc furnace in-situ synthesis, and adjusted the heat treatment process to increase the elongation of the composites by 126% at 293K. Han et al [10] prepared new high-performance layered (TiB+La2O3)/Ti composites by a combination of powder metallurgy and hot rolling.…”