The Microalloying Effect of Ce on the Mechanical Properties of Medium Entropy Bulk Metallic Glass Composites

Abstract

Novel ultra-strong medium entropy bulk metallic glasses composites (BMGCs) Fe65.4−xCexMn14.3Si9.4Cr10C0.9 and Ti40−xCexNi40Cu20 (x = 0, 1.0), through the martensite transformation induced plasticity (TRIP effect) to enhance both the ductility and work-hardening capability, were fabricated using magnetic levitation melting and copper mold suction via high frequency induction heating. Furthermore, the Ce microalloying effects on microstructure and mechanical behaviors were studied. The Fe-based BMGCs consisted of face-centered cubic (fcc) γ-Fe and body-centered cubic (bcc) α-Fe phase, as well as Ti-based BMGCs containing supercooled B2-Ti (Ni, Cu) and a thermally induced martensite phase B19’-Ti (Ni, Cu). As loading, the TRIP BMGCs exhibited work-hardening behavior, a high fracture strength, and large plasticity, which was attributed to the stress-induced transformation of ε-Fe martensite and B19’-Ti (Ni, Cu) martensite. Ce addition further improved the strengthening and toughening effects of TRIP BMGCs. Adding elemental Ce enhanced the mixing entropy ΔSmix and atomic size difference δ, while reducing the mixing enthalpy ΔHmix, thus improving the glass forming ability and delaying the phase transition process, and hence prolonging the work-hardening period before fracturing. The fracture strength σf and plastic stress εp of Ti39CeNi40Cu20 and Fe64.4CeMn14.3Si9.4Cr10C0.9 alloys were up to 2635 MPa and 13.8%, and 2905 MPa and 30.1%, respectively.

Technological Aspects and Performance of High Entropy Alloys with Potential Application in Dental Restorations and Reducing Implant Failure

“…The class of high entropy alloys was introduced based on the idea that when the entropic contribution surpasses the enthalpic value, the formation of intermetallic phases is suppressed, leading to system stabilization. Incorporating less common elements with unique properties in a small amount, typically less than 5%, generates a state of local disorder that contributes to exceptional properties such as enhanced resistance to corrosion, oxidation and abrasion [52,53]. These alloys, composed of multiple elements, exhibit special mechanical and thermal properties, including high strength, hardness, toughness and ultra-high fracture toughness [42].…”

A Fresh Perspective on Medium Entropy Alloys Applications as Coating and Coating Substrate

“…Later, the strategy was to introduce a rarer element, with special properties, in a low proportion, typically less than 5%, besides the principal constituents. Due to the random arrangement of elements, the local disorder is leading to outstanding properties such as corrosion, abrasion, and oxidation resistance [5][6][7]. In addition, due to the variety of elements in such alloys, mechanical and thermal properties, such as high strength/hardness, high toughness, and ultra-high fracture toughness at very high and cryogenic temperatures may manifest [8,9].…”

Computational Simulation by Phase Field: Martensite Transformation Kinetics and Variant Selection under External Fields

“…The transformation-induced plasticity (TRIP) effect is the core mechanism for obtaining a good combination of strength and ductility [1][2][3][4][5][6] in materials such as advanced high-strength automotive steel [7][8][9] and cryogenic steels [10,11]. Therefore, to tailor martensite characteristics using special pretreatment during steel preparation or evaluate the performance of steels in different service environments, a deep understanding of martensite transformation behaviour under external fields, such as different stress-strain and electromagnetic fields, is of critical importance.…”