Abstract A ferrite-austenite 12CrNi2 alloy steel additively manufactured by laser melting deposition (LMD) has been treated by various quenching methods, including direct quenching (DQ), inter-critical quenching (IQ) and step quenching (SQ), respectively, to form the martensite-ferrite dual-phase steel with a similar major volume fraction (62 vol.%) but different grain sizes and lath substructures of martensite. The results demonstrate that SQ, DQ and IQ help to refine the grains of martensite in order, correspondingly decreasing the yield strength, ultimate tensile strength but increasing in the uniform logarithmic strain of the alloy steel. The effect of not only the interface structures and substructures of martensite but also the quenching-route-dependent structures of ferrite on mechanical properties was interpreted in detail. Curiously, the directly quenched steel displays a higher post-uniform logarithmic strain as compared to the inter-critically quenched steel. The abnormal result occurs due to that DQ cannot completely homogenize the microstructural difference between the laser-scanned layers and the interlayer heat-affected zones of the as-deposited alloy steel.

中文翻译：

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不同淬火处理对激光增材制造12CrNi2合金钢组织和力学行为的影响

摘要 采用激光熔化沉积 (LMD) 增材制造的铁素体-奥氏体 12CrNi2 合金钢，分别采用直接淬火 (DQ)、临界间淬火 (IQ) 和阶梯淬火 (SQ) 等多种淬火方法处理，形成马氏体-铁素体双相钢具有相似的主要体积分数 (62 vol.%) 但马氏体的晶粒尺寸和板条亚结构不同。结果表明，SQ、DQ和IQ有助于使马氏体晶粒有序细化，相应降低合金钢的屈服强度、极限抗拉强度，但增加合金钢的均匀对数应变。不仅详细解释了马氏体的界面结构和亚结构，而且还详细解释了铁素体的淬火路线相关结构对机械性能的影响。奇怪的是，与临界间淬火钢相比，直接淬火钢显示出更高的后均匀对数应变。异常结果是由于 DQ 不能完全均匀化激光扫描层和沉积态合金钢层间热影响区之间的显微组织差异。