Introducing ductile crystalline dendrites into glassy matrix to produce in situ bulk metallic glass composites (BMGCs) is an effective strategy to enhance the ductility of bulk metallic glasses (BMGs). However, the microstructural control of the crystalline dendrites is a challenge, and potent toughening of BMGs often requires a high volume fraction of the crystalline phase that impairs the strength and causes the strength-ductility tradeoff. Moreover, existing processing techniques of BMGCs mostly rely on liquid metal casting, which imposes an inherent size limitation due to the required rapid cooling for glass formation. Here we fabricate a multi-layered Zr-based BMGC with a well-controlled gradient in volume fraction of the crystalline dendrites via laser additive manufacturing (LAM) that allows site-specific control of the cooling rate and the resultant microstructure. The gradient BMGC shows an exceptional combination of yield strength (>1.3 GPa) and tensile ductility (~13%). Such enhanced strength-ductility synergy is attributed to the synergetic strengthening from the interaction of the adjacent layers and the asynchronous deformation mode associated with the heterogeneous microstructure. The gradient or functionally-graded structure design motif, enabled by the versatile LAM technology, opens a new window to the development of high-performance BMGCs on a large scale for structural applications.

将可延展的晶体树突引入玻璃状基质中以原位生产大块金属玻璃复合材料（BMGC）是提高大块金属玻璃（BMG）延展性的有效策略。然而，对晶体树枝状晶体的微结构控制是一个挑战，BMG的强韧化通常需要大量的结晶相，这会损害强度并导致强度-延性的折衷。而且，现有的BMGC的加工技术主要依赖于液态金属铸造，由于玻璃形成所需的快速冷却，因此其固有的尺寸限制。在这里，我们通过激光增材制造（LAM）制造了具有良好控制的晶体枝晶体积分数梯度的基于Zr的多层BMGC，可以对冷却速率和所得的微结构进行位置控制。梯度BMGC显示出屈服强度（> 1.3 GPa）和拉伸延展性（〜13％）的出色组合。这种增强的强度-延展性协同作用归因于相邻层之间的相互作用以及与异质微观结构相关的异步变形模式的协同加强。借助多功能LAM技术实现的渐变或功能渐变结构设计主题，为大规模开发用于结构应用的高性能BMGC开辟了新窗口。