超音速微粒轰击诱导表面纳米化对TC11钛合金组织和力学性能的影响

采用超音速微粒轰击(SFPB)表面纳米化技术,在TC11钛合金表层构筑了一定层深的梯度纳米结构,研究了SFPB气体压力对TC11钛合金微观组织和力学性能的影响。结果表明,在低气体压力(0.5 MPa)下,形成了25 μm厚的严重塑性变形层,表层晶粒细化至纳米量级(17.7 nm)。随着气体压力的增大,表层纳米晶尺寸降低,严重塑性变形(SPD)层增大,在高气体压力(1.5 MPa)下,表层纳米晶尺寸和严重塑性变形层深度分别为9.4 nm和51 μm。随着SFPB气体压力的增大,表层显微硬度及硬化层深度逐渐增加,屈服强度、抗拉强度显著增加,而伸长率变化不大,断口形貌从典型的韧性断裂向韧-脆性混合断裂转变。 

Effect of Supersonic Fine Particle Bombardment Induced Surface Nanocrystallization on the Microstructure and Mechanical Properties of TC11 Alloy

The supersonic fine particle bombardment (SFPB) surface nanocrystallization technique is used to construct a gradient nanostructure with a certain layer depth on the surface of TC11 alloy, and the effect of SFPB gas pressure on the microstructure and mechanical properties of TC11 alloy is investigated. The results showed that a 25 μm-thick of severe plastic deformed layer is formed at a small gas pressure (0.5 MPa), and the surface grains are refined to the nanometer scale (17.7 nm). With the increase of gas pressure, the surface nanocrystal size decreases and the SPD layer increases. At the high gas pressure (1.5 MPa), the surface nanocrystal size and the depth of SPD layer are 9.4 nm and 51 μm, respectively. With the increase of SFPB gas pressure, the surface microhardness and the depth of hardened layer gradually increase, and the yield and tensile strengths increase significantly, while the elongation does not change much. The fracture morphology changes from the typical ductile fracture to the mixed ductile-brittle fracture.