采用实验研究的方法，对比分析了激光立体成形TC4钛合金不同热处理状态下的显微组织、静载力学性能和拉伸断口。研究结果表明，沉积态内部有较明显的层带结构，去应力退火和固溶时效均能减弱层带从而均匀化组织；去应力退火处理对强度和塑性提高较少，固溶时效处理则能显著提高综合力学性能。断口分析表明，固溶时效态的室温拉伸试样为韧性断口，而沉积态和去应力退火态拉伸试样拉伸断口均为混合型断口。通过显微组织和拉伸断口分析，重点解释了解理断面形成机理为：裂纹沿α/β界面快速扩展形成解理断面，裂纹尖端的空洞与裂纹连接形成解理面上的韧窝。

The microstructures, tensile strength and fractures of TC4 titanium alloys, fabricated by laser solid forming (LSF), are investigated experimentally in different heat treatment states. The results show that LSF Ti alloy TC4 contains layer bands which stress relief annealing and solid solution aging can help eliminate so that the microstructures become more homogeneous, while the former makes less contribution to the improvement of strength and ductility, the latter can get comprehensive mechanical properties. The tensile fracture shows that the fractures of solution-aging specimens are almost ductile fractures while the as-deposited and stress relief annealing specimens are all mixed fractures. The formation mechanism of cleavage is explained by researching microstructures and fractures which is that cracks propagation along the interface of α/β forms the cleavage plane and the pores joined to the crack forms the dimples.