含氢马氏体时效钢低温力学性能行为与断裂机制SCIEI

两种状态的钢的强度和塑性均随温度降低而升高,随氢含量的增加而降低。时效样品虽比固溶样品的氢脆敏感性高,但即使在77K下前者仍有良好的抗氢性能。塑性变形后位错缠结成位错胞,其胞尺寸随温度下降而减小,随氢含量的升高而增大。没有发现低温形变孪晶。295和223K下,氢含量为5.90ppm的固溶和时效态试样拉伸断口分别为准解理和沿晶断裂,其它实验条件下的皆为穿晶断裂。并讨论了氢对材料力学性能行为的影响及断裂机制。

CRYOGENIC MECHANICAL BEHAVIOUR OF MARAGING STEEL CONTAINING HYDROGEN

Within the range of 77 to 295 K, the strength and plasticity of 18Nimaraging steel containing hydrogen increase with the decreasing temperature anddecrease with the increasing hydrogen content. The susceptibility to hydrogen em-brittlement of the maraged specimens is superior to solid solution treated ones evendown to 77K. The dislocations after plastically deformed will be tangled into cellswhich reduce themself in size as decreasing temperature and coarsen as increasinghydrogen concentration. No cryogenic deformation twin was found. The tensile frac-ture surfaces of the solution and maraged specimens containing 5.90 ppm hydrogenunder 295--223 K are revealed as quasi-cleavage and intergranular features respec-tively and as transgranular one at all under other experimental conditions. Theinfluence of hydrogen on the mechanical behaviour of steel and the mechanism ifhydrogen induced deformation and fracture were also discussed.