随着能源的短缺和环境污染的日益严重，汽车轻量化需求日益迫切，如何通过工艺及成分设计革新、获得兼具高强度和高塑性的钢板尤为重要。尝试将Cu作为合金元素加入TRIP钢中，采用淬火配分（ Q＆P ）工艺对含Cu TRIP钢进行一步法和两步法热处理，通过拉伸试验、X射线衍射分析、扫描电镜、透射电镜等实验手段，对热处理后的组织及性能进行测试和观察，探究了不同热处理工艺对组织和性能的影响。研究结果表明：一步法处理后的显微组织为铁素体、马氏体和残余奥氏体，两步法处理后不仅包含上述3种组织，还含有贝氏体。一步法处理后，抗拉强度达2200 MPa，拉伸延展率为15％，强塑积为33 GPa ？％；两步法处理后综合力学性能优于一步法，在400℃等温5 min 后，抗拉强度为1300 MPa，拉伸延展率为43％，强塑积超过55 GPa？％。实验钢良好的综合力学性能得益于铁素体、马氏体／贝氏体和残余奥氏体的合理配比，变形过程中残余奥氏体的相变诱导塑性效应，以及马氏体位错与Cu粒子的交互作用。
A Cu-TRIP steel was heat-treated by quenching and partitioning ( Q&P ) processes including one-step (QT=PT, Quenching Temperature, Partitioning Temperature) and two-step(QT≠PT). Microstructures and properties differences were investigated by means of tensile tests, X-Ray diffraction ( XRD ) , scanning electron microscopy ( SEM ) , and transmission electron microscopy ( TEM ) . Results show that microstructure after one-step consists of martensite, ferrite, and retained austenite while that after two-step contains bainite except for the aforementioned three microstructures. Tensile strength and elongation are 2 200 MPa and 15%respectively after one-step, accompanied with a product of strength and elongation of 33 GPa?%. As far as two-step is concerned, a combination of tensile strength of 1 300 MPa and elongation of 43% is obtained at partitioning temperature of 400℃ with the highest product of strength and elongation of ~55 GPa?% which is prior to one-step. The eminent mechanical properties benefit from relative contents of phases, TRIP effect, and interaction between Cu precipitates and dislocation in martensite.
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