Abstract: Mathematical models are among the new approaches employed to predict the properties of any material under various conditions. Mathematical models are essential for not only understanding the material properties but also estimating the cost of design, product life, and failure criteria of the product. Therefore, in the current investigation, the hot deformation (HD) behaviour and microstructure alteration of deformed AA7150-5 wt% B4C composite was studied through a mathematical model. The new AA7150-5 wt% B4C composite was fabricated through an ultrasonic-probe assisted (20 KHz, 1000 W) stir casting process. The hot compression test was performed on a hydraulic press for various deformation temperatures (623–773 K) and strain rates (0.01–1 s− 1). Based on the outcome, it is inferred that the flow stresses and microstructures of AA7150-5 wt% B4C composite was significantly altered during the hot compression test under various deformation conditions. The constitutive and dynamically recrystallized grain (DRXed) models were developed as a function of various deformation conditions of deformed AA7150-5 wt% B4C composite, which was then applied to forecast the flow stress and grain size behaviour for different deformation conditions. The flow stress and DRXed grain size were obtained through the proposed constitutive and DRXed models are correlated with experimental results, with excellent accuracy. The models developed are reliable to predict the AA7150-5 wt% B4C properties for various conditions. Graphic abstract: [Figure not available: see fulltext.]. © 2021, The Korean Institute of Metals and Materials.