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通过光学显微镜和TEM观察以及机械性能试验,研究了475℃长期时效处理(直至720h)对O0Cr23Ni8Mo3AlTi双相不锈钢显微组织和机械性能的影响。结果表明,475℃长期时效处理使合金的硬度增加,塑性和韧性显著恶化。该现象具有典型的475℃脆性断裂特征,直至720h仍然保持该特征。这主要由475℃长期时效处理期间在a-铁素体母体上析出的a′相(b、c、c)及其长大特征所致。在a-铁素体母体上同时析出的Ni_3Al相(f、c、c)产生了叠加的影响。
The effects of long-term aging at 475 ℃ (up to 720h) on the microstructure and mechanical properties of O0Cr23Ni8Mo3AlTi duplex stainless steel were investigated by optical microscope, TEM observation and mechanical tests. The results show that the long-term aging treatment at 475 ℃ increases the hardness of the alloy and deteriorates ductility and toughness remarkably. This phenomenon has the typical 475 ° C brittle fracture feature, which remains up to 720 h. This is mainly due to the a ’phase (b, c, c) precipitated on the a-ferrite matrix during the long-term aging treatment at 475 ° C and its growth characteristics. The Ni 3 Al phases (f, c, c) precipitated simultaneously on the a-ferrite matrix exert a superposition effect.