There is a long and lively debate in the literature about the origin of the Bauschinger effect in polycrystalline materials, the most widely accepted explanation being the easier movement of dislocations during reverse loading causing the reduction of the yield stress. Other explanations include incompatible deformation at the grain scale and change of dislocation cell structures during forward and reverse loading, but recent publications show these phenomenological explanations of the Bauschinger effect are not holistic. In the experimental work presented here, we have investigated the role of micro residual lattice strain on the origin of the Bauschinger effect in type 316H austenitic stainless steel using in-situ neutron diffraction. Standard cylindrical specimens were tension-compression load cycled at room temperature with the loading interrupted at incrementally larger compressive and tensile strains followed by reloading to the tensile loop peak strain. Mirror symmetric cyclic tests were also performed with tensile and compressive load interruptions followed by compressive reloading to the compressive loop peak strain. A strong correlation is demonstrated between the evolution of residual lattice strain in the grain families and the change in magnitude in macroscopic yield stress, peak stress and the shape of the yielding part of the stress-strain curve for both the cyclic tension yield and compression yield tests. This implies that the residual lattice strain generated by grain scale elastic and plastic deformation anisotropy is the primary source of the Bauschinger kinematic hardening effect observed in type 316H austenitic stainless steel.

关于多晶材料中的鲍辛格效应的起源，文献上有一个长期而活跃的争论，最广泛接受的解释是在反向加载过程中位错更容易移动，从而导致屈服应力的降低。其他解释包括晶粒尺寸的不相容变形以及正向和反向加载过程中位错细胞结构的变化，但是最近的出版物表明，对鲍辛格效应的这些现象学解释并不全面。在此处介绍的实验工作中，我们使用原位中子衍射研究了微小残余晶格应变对316H型奥氏体不锈钢的鲍辛格效应起源的作用。标准圆柱试样在室温下承受拉压载荷，并在逐渐增大的压缩应变和拉伸应变时中断，然后重新加载至拉伸环峰值应变。还进行了镜面对称循环试验，其中拉伸和压缩载荷中断，然后压缩重新加载到压缩环峰值应变。在循环拉伸屈服和压缩屈服下，晶粒家族中残余晶格应变的发展与宏观屈服应力，峰值应力的大小变化以及应力-应变曲线的屈服部分的形状之间显示出很强的相关性。测试。