Multi-scale reinforcements stimulated dynamic recrystallization and mechanical behavior of as-extruded titanium matrix composites

Peikun Qiu,Guangfa Huang,Yuanfei Han,Jianwen Le,Linxiu Du ,Weijie Lü

doi:10.1051/matecconf/202032108005

Peikun Qiu, Guangfa Huang + Show 4 more

Open Access

https://doi.org/10.1051/matecconf/202032108005

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Abstract

Different volume fraction of TiB, TiC and La2O3 multiple-reinforced Ti6Al4V composites were fabricated by casting and followed by forging and hot extrusion. The microstructural evolution and mechanical behavior of (TiB+TiC+La2O3)/Ti6Al4V composites during hot extrusion were investigated. The microstructural observations showed that the TiBw and TiCp agglomeration disappeared and distributed more homogeneously in the Ti matrix after hot extrusion. Besides, TiBw exhibited highly preferred alignment along the extrusion direction and TiCp distributed along the same direction. Besides, two kinds of microstructure bands with distinctive spatial distributions of reinforcements were formed after hot extrusion: equiaxial bands embedded with fairly substantial reinforcements and finer basket-weave bands containing few reinforcements, in which the micron-scale TiBw, TiCp and submicron-scale La2O3 particle stimulating nucleation occurred and resulting dynamic recrystallization were the main mechanisms responsible for grain refinement. The tensile tests revealed that hot extrusion significantly increased elongation of (TiB+TiC+La2O3)/Ti6Al4V composites from 2.71% to 13.2% accompanied by slightly decreasing ultimate tensile strength from 954MPa to 903MPa, compared with that of the as-forged composites, which due to a complex process of reinforcements/matrix interaction during extrusion and dynamic recrystallization.

Highlights

Different volume frac on of TiB, TiC and La2O3 mul ple-reinforced Ti6Al4V composites were fabricated by cas ng and followed by forging and hot extrusion
Introduc on Titanium matrix composites(TMCs) with preeminent proper es such as high specific strength, high specific s ffness, outstanding oxida on and corrosion resistance, and admiring elevated temperature durability have been considered as poten al materials for extending applica on on aerospace and advanced weapon systems [1,2,3]
2.1 Prepara on and processing of the TMCs (TiB+TiC+ La2O3)/Ti6Al4V composites with different volume frac on of reinforcements were in situ fabricated by consumable vacuum arc remel ng (VAR) furnace using common cas ng technique

Summary

Material and experiments

2.1 Prepara on and processing of the TMCs (TiB+TiC+ La2O3)/Ti6Al4V composites with different volume frac on of reinforcements were in situ fabricated by consumable vacuum arc remel ng (VAR) furnace using common cas ng technique. The propor onal raw materials were mixed firstly, and pressed into preformed bars on press machine followed. During the mel ng process, the chemical reac on among LaB6, B4C and Ti occurred as followed: In order to obtain cast ingots with high chemical homogeneity, the composites were melted three mes. The as-forged composites billets were extruded with an extrusion ra o of 7:1 at 1253 K, a er which rods of diameter 30 mm were obtained

Characteriza on

Phase iden fica on

Mechanisms of reinforcements s mulated dynamic recrystalliza on

Conclusion