Bridgman法制备塑性钛基轻质非晶复合材料

通过Bridgman定向凝固法成功制备了内生枝晶增塑的轻质钛基非晶复合材料. 与传统的Cu模吸铸法相比, Bridgman法有效消除了铸态组织中的孔洞, 得到了更均匀的微观组织, 且能通过调节抽拉速度来控制枝晶相的尺寸和分布, 进而优化其力学性能. 当抽拉速度为1.4 mm/s时, 合金压缩屈服强度、断裂强度和断裂塑性分别达到1956 MPa, 2706 MPa和18.0%, 且有明显的加工硬化现象. 进一步讨论了枝晶跨越长度$L$和枝晶间距$S$与力学性能的关系, 发现L在约40 μm时对材料的塑性贡献最大.

SYNTHESIS OF PLASTIC LIGHTWEIGHT Ti-BASED METALLIC-GLASS-MATRIX COMPOSITES BY BRIDGMAN SOLIDIFICATION

A series of lightweight Ti-based ductile in-situ dendrite-reinforced metallic-glass-matrix composites were synthesized by Bridgman solidification. Compared to Cu-mould suction casting, the $beta$-Ti dendrites were uniformly distributed within the glass matrix by this method. Through tailoring the withdrawal velocity, the volume fraction and the characteristic spanning length of dendrites could be changed, which provides a way to optimize the mechanical properties of the composites. The Ti-based composite with excellent mechanical performances (high ultimate strength of 2706 MPa and large plasticity of 18.0% with apparent work-hardening behavior) was synthesized when the withdrawal velocity was fixed at 1.4 mm/s. The relationship between the size of the dendrites and the mechanical properties was investigated, and it was found that the improved mechanical properties were obtained when the size of the dendrited approached about 40 μm.