Brittle-to-ductile transition in a Ti–TiB metal-matrix composite

A Ti-15Mo/TiB titanium–matrix composite (TMC) was produced by spark plasma sintering at 1400 °C under a load of 40 MPa for 15 min using a Ti-14.25(wt.)%Mo-5(wt.)%TiB2 powder mixture. Microstructure evolution and mechanical behavior of the composite were studied during uniaxial compression at room temperature and in a temperature range of 500–1000 °C. At room temperature, the composite showed a combination of high strength (the yield strength was ~1500 MPa) and good ductility (~22%). The microstructure evolution of the Ti-15Mo matrix was associated with the development of dynamic recovery at 500–700 °C and dynamic recrystallization at higher temperatures (≥800 °C). The apparent activation energy of the plastic deformation was calculated and a processing map for the TMC was constructed using the obtained results.

Section: Materials and Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior and Microstructure Evolution of a Ti-15Mo/TiB Titanium–Matrix Composite during Hot Deformation

Zherebtsov

Ozerov

Klimova

et al. 2019

“…Therefore, in contrast to many other sintering treatments, noticeable microstructure coarsening can be avoided during the SPS. However, high strength of Ti/TiB MMCs is usually accompanied by low ductility at room temperature [11,15].…”

Section: Introductionmentioning

confidence: 99%

“…Thermomechanical treatment can considerably improve ductility and strength and decrease ductile-to-brittle transition temperature of MMCs [15][16][17][18]. However, the microstructure evolution of MMCs during deformation under different conditions has not been studied comprehensively so far [19].…”

Section: Introductionmentioning

confidence: 99%

Effect of High-Pressure Torsion on Structure and Microhardness of Ti/TiB Metal–Matrix Composite

Zherebtsov

Ozerov

Stepanov

et al. 2017

Effect of high-pressure torsion (HPT) at 400 • C on microstructure and microhardness of a Ti/TiB metal-matrix composite was studied. The starting material was produced by spark plasma sintering of a mixture of a pure Ti and TiB 2 (10 wt %) powders at 1000 • C. The microstructure evolution during HPT was associated with an increase in dislocation density and substructure development that resulted in a gradual microstructure refinement of the Ti matrix and shortening/redistribution of TiB whiskers. After five revolutions, a nanostructure with (sub) grain size of~30 nm was produced in Ti matrix. The microhardness increased with strain attaining the value~520 HV after five revolutions. The contribution of different hardening mechanisms into the hardness of the Ti/TiB metal-matrix composite was quantitatively analyzed.

“…That is why in situ PM processes are currently considered ones of the best techniques due to the excellent properties of the produced materials. The main advantage of these kinds of composites lies in the stable interface formed between the matrix and the reinforcing phase [10][11][12][13][14][15][16][17]. Among diverse materials that could act as reactive compounds with titanium, boron (B) has been considered as a suitable candidate to start in situ secondary reinforcing phases.…”

Section: Introductionmentioning

confidence: 99%

Study of the Influence of TiB Content and Temperature in the Properties of In Situ Titanium Matrix Composites

Arévalo

Montealegre-Meléndez

Ariza

et al. 2017

This work focuses on the study of the microstructure, hardening, and stiffening effect caused by the secondary phases formed in titanium matrices. These secondary phases originated from reactions between the matrix and boron particles added in the starting mixtures of the composites. Not only was the composite composition studied as an influencing factor in the behaviour of the composites, but also different operational temperatures. Three volume percentages of boron content were tested (0.9 vol %, 2.5 vol %, and 5 vol % of amorphous boron). The manufacturing process used to produce the composites was inductive hot pressing, which operational temperatures were between 1000 and 1300 • C. Specimens showed optimal densification. Moreover, microstructural studies revealed the formation of TiB in various shapes and proportions. Mechanical testing confirmed that the secondary phases had a positive influence on properties of the composites. In general, adding boron particles increased the hardness and stiffness of the composites; however rising temperatures resulted in greater increases in stiffness than in hardness.