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TiB/Ti6Al4V composite was prepared using spark plasma sintering followed by bidirectional reaction hot rolling. The TiB whiskers were synthesized in situ during the rolling process, thereby preserving a relatively high structural integrity. TiB whiskers were distributed within the composite in three distinct locations: intragranular, intergranular, and transgranular distribution. After eight passes of vertical bidirectional reaction hot rolling, the average grain size of the matrix was refined to 1.36 μm, and the grains exhibited random crystallographic orientations. Tensile properties in different directions demonstrated high consistency, with a strength of 1220 MPa ± 30 MPa and an elongation of 8.0% ± 0.5%. The primary strengthening mechanisms in the composite included grain refinement, dislocation strengthening, and load transfer strengthening from the TiB. • Dense TiB 2 /Ti6Al4V billets were achieved via SPS. • A multi-pass bidirectional in-situ reaction hot rolling method was employed to prepare TiB/Ti6Al4V composite. • The TiB/Ti6Al4V composite showed consistent strength and ductility in all directions. [ABSTRACT FROM AUTHOR]

The individual effects of Y and Nd elements on the precipitate-free zone (PFZ) development and the dislocation creep mechanism of a Mg-4Y-3.5Nd alloy were investigated using tensile creep loading at 553 K. Some of the samples were treated with a solid solution (WNS) and others were treated by peak aging (WNA). Before creep, no precipitates were found in the WNS sample, whereas both lamellar binary phases and platelet ternary phases were found in the WNA sample and PFZs were already formed. After creep, cross slip and pyramidal < c + a > slip were detected as the dominant creep mechanisms in the WNS sample under all stress regimes. Only cross slip dominated the creep of the WNA sample under low-stress regimes, whereas pyramidal slip also became dominant under high-stress regimes. Dynamic precipitation of ternary phases was observed, and PFZs gradually developed in the WNS sample under all stress regimes. Ternary phases persisted in the WNA sample under all stress regimes, but the dissolution of binary phases and widening of PFZs were significant under high-stress regimes. Consequently, greater creep resistance was achieved in the WNA sample under low-stress regimes but in the WNS sample under high-stress regimes. Compared to Mg-7.5Y and Mg-3.5Nd binary alloys, the synchronous addition of Y and Nd to form a Mg-4Y-3.5Nd alloy diversified the slip types. The Y element reduced the widening rate of PFZs, but it could not thoroughly prohibit the formation of PFZs. The Nd element accelerated both static and dynamic precipitation, but it also triggered the rapid widening of PFZs. • Individual effect of Y and Nd elements on creep behavior of Mg-4Y-3.5Nd alloy is revealed. • The Y element delays PFZ widening while the Nd element promotes dynamic precipitation. • The synchronous addition of Y and Nd elements diversifies the active slip types. • Static precipitates are stable and aging strengthening is effective under low stress. • Precipitate dissolution and PFZ widening weaken creep resistance under high stress. [ABSTRACT FROM AUTHOR]