高锰钢的双n行为

The Double in Bouble in Behaviour

研究了高锰钢在拉伸过程中形变硬化行为及组织结构变化，结果表明，其真应力、真应变分段符合Ｈｏｌｌｏｍｏｎ方程，表现为双ｎ行为，高锰钢优异的形变硬化性能表现在ｎ＿２阶段，为孪晶强化，在位错强化的几阶段，其形变硬化不显著。在拉伸曲线上出现锯齿形状的同时，试样表面也出现平行的痕迹，这两个特点又表明具有面心结构的高锰钢拉伸形变时。似有早为人知的Ｐｏｒｔｅｖｉｎ－ＬｅＣｈａｔｅｌｉｅｒ效应。

The strain hadening and changes in the structure during the process of the uniaxial ten-sion of the high Mn steel were studied in this paper,Results showed that the relation betweenits true stress and true strain accorded with Hollomon equation in sections,behaving as doub-le n.The property of the excellent strain hardening which was twinning hardening in the highMn steel behaved as n_2 section. In the n_1 section of thre dislocation strengthening,its strain hard-ening was not marked. A lot of parallel indentation appeared on the surface of the specimenwhen the tension curve became sawtooth shape.The two characters showed that the high Mnsteel having a face-centered cubic lattice seemed to have the portevin-le Chadier effect knownearly.