Zr 46.9 Cu 45.5 Al 5.6 Y 2.0 金属玻璃含B2-CuZr相内生复合材料的制备及其力学性能 *

Abstract

Bulk metallic glass (BMG) composites containing B2-CuZr phase are of interest due to they behave large plastic strain and apparent work hardening in tension. Nevertheless till now most BMG composites containing B2-CuZr phase are based on Cu47.5Zr47.5Al5 or Zr48Cu47.5Al4Co0.5 BMG, which has limited glass forming ability (GFA). The prepared sample size is small, which restricts their potential engineering structural applications. In this work, Zr-Cu-Al-Y quaternary system is selected due to its high GFA. By tuning composition close to CuZr alloy in Zr-Cu-Al-Y quaternary system, Zr46.9Cu45.5Al5.6Y2.0 BMG is selected because it has proper GFA (critical diameter Dc=5 mm) and relatively large fracture toughness (KQ=(49±3) MPa·m). By decreasing the cooling rates of the melt via increasing diameter of casting rods, large-sized in situ Zr46.9Cu45.5Al5.6Y2.0 BMG composites containing 13% and 25% volume fractions spherical B2-CuZr phase were prepared in the casting rods with 6 and 7 mm in diameters, respectively. In compression testing, the in situ BMG composites containing 25%B2-CuZr phase promote multiple shear bands within glass matrix and remarkable global plastic deformation, accompanied by a large compressive plastic strain as 6.5%. Nevertheless in tension testing no obvious global ductility was achieved, which attri*国家自然科学基金资助项目51171180 收到初稿日期: 2015-03-11,收到修改稿日期: 2015-07-04 作者简介:沈勇,男, 1976年生,助理研究员 DOI: 10.11900/0412.1961.2015.00140 第1407-1415页 pp.1407-1415