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从热力学、晶体学、表面浮凸等方面逐一对切变机制进行了理论探讨及试验观察分析,从多角度、多方面综合分析了马氏体切变机制存在的缺陷。研究发现马氏体相变的切变机制缺陷:①各种晶体学切变模型的切变过程需要极大的切变能量,在208~320 kJ/mo之l间,为相变驱动力所不及。切变机制的相变阻力太大,约2.335 kJ/mol,相变驱动力难以克服相变阻力完成切变过程;②各种晶体学切变模型均与实际不符;③表面浮凸是试样表面的过冷奥氏体转变产物的一种普遍表象,马氏体表面浮凸跟珠光体、贝氏体的浮凸比较,没有特殊之处,呈帐篷形,不具备切变特征。表面预先划痕在马氏体形成后出现断裂、弯曲,并非连续的折线,呈非N形。马氏体切变机制应予摈弃,建立马氏体相变新机制。
From the aspects of thermodynamics, crystallography and surface relief, the shear mechanism is studied theoretically and experimentally. The defects of the martensitic shear mechanism are comprehensively analyzed in many aspects. It is found that the shear mechanism of martensitic transformation is flawed: ① The shear process of various crystallographic shear models requires great shear energy, which is the phase transition driving force at 208-320 kJ / Less than. The phase transformation resistance of the shear mechanism is too large, about 2.335 kJ / mol, the phase change driving force is difficult to overcome the phase change resistance to complete the shear process; ②All kinds of crystallographic shear models are inconsistent with the actual; ③ Surface relief is the sample The surface of the supercooled austenite transformation product of a common appearance, martensite surface relief with pearlite, bainite embossment comparison, there is no special place, tent-shaped, do not have the shear characteristics. Pre-scratched surface of the martensite after the formation of fracture, bending, not a continuous line, was non-N-shaped. Martensitic shear mechanism should be abandoned to establish a new mechanism of martensitic transformation.