Fracture toughness and fatigue-crack propagation in a Zr–Ti–Ni–Cu–Be bulk metallic glass

Applied Physics Letters - Tập 71 Số 4 - Trang 476-478 - 1997
Christopher J. Gilbert1, Robert O. Ritchie1, William L. Johnson2
1Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720-1760
2Department of Materials Science, California Institute of Technology, Pasadena, California 91125

Tóm tắt

The recent development of metallic alloy systems which can be processed with an amorphous structure over large dimensions, specifically to form metallic glasses at low cooling rates (∼10 K/s), has permitted novel measurements of important mechanical properties. These include, for example, fatigue-crack growth and fracture toughness behavior, representing the conditions governing the subcritical and critical propagation of cracks in these structures. In the present study, bulk plates of a Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy, machined into 7 mm wide, 38 mm thick compact-tension specimens and fatigue precracked following standard procedures, revealed fracture toughnesses in the fully amorphous structure of KIc∼55 MPa√m, i.e., comparable with that of a high-strength steel or aluminum alloy. However, partial and full crystallization, e.g., following thermal exposure at 633 K or more, was found to result in a drastic reduction in fracture toughness to ∼1 MPa√m, i.e., comparable with silica glass. The fully amorphous alloy was also found to be susceptible to fatigue-crack growth under cyclic loading, with growth-rate properties comparable to that of ductile crystalline metallic alloys, such as high-strength steels or aluminum alloys; no such fatigue was seen in the partially or fully crystallized alloys which behaved like very brittle ceramics. Possible micromechanical mechanisms for such behavior are discussed.

Từ khóa


Tài liệu tham khảo

1993, Appl. Phys. Lett., 63, 2342, 10.1063/1.110520

1975, J. Appl. Phys., 46, 1625, 10.1063/1.321764

1974, J. Mater. Sci., 9, 718, 10.1007/BF00761791

1995, Appl. Phys. Lett., 67, 1544, 10.1063/1.114487

1996, Appl. Phys. Lett., 68, 493, 10.1063/1.116377

1994, Scr. Metall., 30, 429, 10.1016/0956-716X(94)90598-3

1975, J. Mater. Sci., 10, 1557, 10.1007/BF01031856

1975, Scr. Metall., 9, 109, 10.1016/0036-9748(75)90578-5

1963, J. Basic Eng., 85, 528, 10.1115/1.3656900

1995, J. Am. Ceram. Soc., 78, 2291, 10.1111/j.1151-2916.1995.tb08660.x

Thông tin
Thông tin xuất bản

Applied Physics Letters

Tập 71 Số 4

476-478

Thông tin tác giả