Strong work-hardening effect in a multiphase ZrCuAlNiO alloy

Abstract

A bulk as-cast ZrCuAlNiO alloy consisting of Zr2Cu, B2-type ZrCu, and a small quantity of ZrCu martensite phase was prepared by copper mold casting. The multiphase alloy exhibits a remarkable work-hardening effect (Δσy=1196MPa, ΔE=5.6GPa, and Δεe=2.11%) in the cycle loading-unloading compression test and possesses the high work-hardening capacity (Hc) of 1.66 and 1.58 at strain rates of 1×10−4 and 1×10−3s−1, respectively, under continuous deformation. The strong work-hardening effect of the alloy results from the continuous transformation of the ZrCu (B2, austenite) phase into the ZrCu martensite.

Deformation-induced martensitic transformation in Cu–Zr–(Al,Ti) bulk metallic glass composites

“…It is important to note here that the B2 CuZr phase can only be obtained from the glassy state by proper adjustment of the cooling rate. Annealing treatments of glassy alloys lead to the formation of metastable phases or the precipitation of the equilibrium phases, depending on the composition [20].To the best of the authors' knowledge only the formation of martensite in Cu-Zr-based partially glassy alloys upon quenching has been reported so far [19,[21][22][23][24]. This is due to the stresses in the material that occur during the solidification process that usually trigger martensite formation.…”

“…To the best of the authors' knowledge only the formation of martensite in Cu-Zr-based partially glassy alloys upon quenching has been reported so far [19,[21][22][23][24]. This is due to the stresses in the material that occur during the solidification process that usually trigger martensite formation.…”

“…Next to the martensite formation upon quenching, which is well known and has been reported for many different systems [9,21,23,24,[30][31][32], the martensitic transformation can be also induced by deformation. Figure 3 displays high-energy X-ray diffraction patterns of as-cast and deformed Cu 47.5 Zr 47.5 Al 5 and Cu 50 Zr 45-Ti 5 bulk specimens.…”

Effect of Tempering on Microstructure and Mechanical Properties in a Multiphase ZrCuAlNiO Alloy

“…It has been demonstrated that oxygen impurity at a level of 0.3 at% dramatically reduces the glass forming ability (GFA). 21,22) Therefore, it can be deduced that the presence of 0.56 at% oxygen in the ZrCuAlNiO alloy deteriorates the GFA and triggers the formation of the crystalline phases. In addition, the oxygen addition may stabilize the ZrCu (B2) crystalline phase.…”

“…12,13) The ZrCu martensites and ZrCu (B2) phases could be used as reinforcement in the Zr-Cu(Ni) based alloys to improve the strength and toughness of the materials. [15][16][17][18][19][20][21] In addition, the Zr-Cu(Ni) system exhibits particular promise for developing precipitation-strengthened multiphase alloys. However, a problem is the incomplete knowledge of the stability of various phases in Zr-Cu(Ni) system alloy at high temperatures.…”