Abstract The plastic deformation behavior of single crystals of the δ1p and δ1k phase compounds in the Fe–Zn system, which are the major constituent phases in the coating layer of galvannealed (GA) steels, has been investigated by micropillar compression tests at room temperature as a function of crystal orientation and specimen size. (0001)[11 2 ‾ 0] basal slip and (10 1 ‾ 0)[ 1 ‾ 2 1 ‾ 0] prism slip are observed to operate in the δ1p phase compound while (0001)[11 2 ‾ 0] basal slip is observed in the δ1k phase compound. For all cases, a significant strain burst occurs immediately after yielding, forming giant steps on the slip planes along the slip direction and leading in many cases to instantaneous ‘slip plane (shear) failure’. The extent of such strain burst as well as instantaneous ‘slip plane failure’ is reduced by introducing dislocations (pre-straining) prior to micropillar testing, accompanied by the reduction in the stress at which such strain burst occurs as well as that in the extent of strain burst. The critical resolved shear stress (CRSS) for basal and prism slip in the δ1p and δ1k phase compounds all show an inverse power-law scaling against the specimen size with an exponent in the range of 0.02–0.06. The bulk CRSS values are estimated respectively to be approximately 320, 430, and 765 MPa for the basal slip in the δ1p and δ1k compounds and the prism slip in the δ1p compound by taking into account the specimen size effects of CRSS.

中文翻译：

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Fe-Zn系统中δ1p和​​δ1k金属间化合物单晶的塑性变形通过微柱压缩

摘要 Fe-Zn 系中 δ1p 和 δ1k 相化合物单晶的塑性变形行为是合金化 (GA) 钢镀层中的主要组成相，已通过室温微柱压缩试验研究如下：晶体取向和试样尺寸的函数。观察到 (0001)[11 2 ‾ 0] 基底滑移和 (10 1 ‾ 0)[ 1 ‾ 2 1 ‾ 0] 棱柱滑移在 δ1p 相化合物中起作用，而 (0001)[11 2 ‾ 0] 基底滑移在 δ1k 相化合物中观察到。对于所有情况，屈服后立即发生显着的应变爆发，沿滑动方向在滑动平面上形成巨大的台阶，并在许多情况下导致瞬时“滑动平面（剪切）破坏”。通过在微柱测试之前引入位错（预应变）来减少这种应变爆发以及瞬时“滑移面失效”的程度，伴随着发生这种应变爆发时的应力以及程度的降低应变爆发。δ1p 和 δ1k 相化合物中基底和棱柱滑移的临界分辨剪切应力 (CRSS) 都显示出相对于试样尺寸的逆幂律标度，其指数范围为 0.02-0.06。考虑到 CRSS 的试样尺寸效应，δ1p 和 δ1k 化合物中的基底滑移和 δ1p 化合物中的棱柱滑移的整体 CRSS 值估计分别约为 320、430 和 765 MPa。伴随着发生这种应变爆裂的应力以及应变爆裂程度的降低。δ1p 和 δ1k 相化合物中基底和棱柱滑移的临界分辨剪切应力 (CRSS) 都显示出相对于试样尺寸的逆幂律标度，其指数范围为 0.02-0.06。考虑到 CRSS 的试样尺寸效应，δ1p 和 δ1k 化合物中的基底滑移和 δ1p 化合物中的棱柱滑移的整体 CRSS 值估计分别约为 320、430 和 765 MPa。伴随着发生这种应变爆裂的应力以及应变爆裂程度的降低。δ1p 和 δ1k 相化合物中基底和棱柱滑移的临界分辨剪切应力 (CRSS) 都显示出相对于试样尺寸的逆幂律标度，其指数范围为 0.02-0.06。考虑到 CRSS 的试样尺寸效应，δ1p 和 δ1k 化合物中的基底滑移和 δ1p 化合物中的棱柱滑移的整体 CRSS 值估计分别约为 320、430 和 765 MPa。