**Tuomo Nyyssönen 1,2,\*, Olli Oja 3, Petri Jussila 3, Ari Saastamoinen 1, Mahesh Somani <sup>4</sup> and Pasi Peura <sup>1</sup>**


Received: 27 February 2019; Accepted: 19 March 2019; Published: 22 March 2019

**Abstract:** The quenching and partitioning response following intercritical annealing was investigated for three lean TRIP-type high-Al steel compositions. Depending on the intercritical austenite fraction following annealing, the steels assumed either a ferrite/martensite/retained austenite microstructure or a multiphase structure with ferritic, bainitic and martensitic constituents along with retained austenite. The amount of retained austenite was found to correlate with the initial quench temperature and, depending on the intercritical annealing condition prior to initial quenching, with the uniform and ultimate elongations measured in tensile testing.

**Keywords:** steel; martensite; austenite; quenching; partitioning; dilatometry
