表面机械强化工业纯钛疲劳性能的研究

利用透射显微技术和 X射线衍射分析技术 ,对工业纯钛在喷丸、滚压两种强化方式下的组织和残余应力进行了对比研究。结果表明 :1 ) TEM组织中均可观察到位错和变形孪晶。滚压形成了单个分散的孪晶 ,喷丸表层中形成大量相互交叠的孪晶和变形带 ;疲劳后 ,喷丸组织中产生孪晶 -孪晶的交互作用 ,而滚压组织中是孪晶 -晶界的交互作用。2 )喷丸较滚压强化表层残余应力松弛显著 ,疲劳后两者的表层残余应力相当 ;3)喷丸较滚压粗糙度高一个数量级。并依上述分析对表面机械强化机理进行了解释。

Effect of mechanical surface treatments on fatigue properties of commercial purity titanium

The fatigue strength of commercial purity titanium was variously improved by shot peened (SP) or cold rolled (CR) In an effort to determine the mechanisms, microstructures, compressive residual stress and surface roughness have been characterized, and the following results were obtained: 1) At the microscopic level of TEM, both dislocations and deformation twins are observed: Odd and dispersed twins are formed in the CR,but piles up twins and deformation bands are observed in the SP After 106 cyclic deformations, twin twin interactions in the SP and twin grain boundary interactions in the CR play an important role, respectively 2) Surface residual stress has higher relaxation in the SP than in the CR condition during fatigue deformation, but the surface compressive residual stress has the same values after fatigue deformation 3) Roughness resulting from SP is ten times of CR