The Effect of Two-Step Austempering Temperature and Copper Addition on the Microstructure and Mechanical Properties of ADI

Subject Areas : journal of New Materials

Mehdi Ghorbani Jamal-Abadi ¹ , Amir Abedi ² , Soroush Parvizi ³ , Mina Safa ⁴ , Saloumeh Mesgari Abbasi ⁵ , Gholamreza Khalaj ⁶

1 - Materials Engineering Department, Faculty of Materials Engineering and Interdisciplinary Sciences, Shahid Rajaee Teacher Training University (SRTTU), Tehran, 16785-136, Iran
2 - Materials Engineering Department, Faculty of Materials Engineering and Interdisciplinary Sciences, Shahid Rajaee Teacher Training University (SRTTU), Tehran, 16785-136, Iran
3 - Materials Engineering Department, Faculty of Materials Engineering and Interdisciplinary Sciences, Shahid Rajaee Teacher Training University (SRTTU)
4 - Department of Physics, Sav.C., Islamic Azad University, Saveh, Iran
5 - Department of Materials Engineering, Sav.C., Islamic Azad University, Saveh, Iran
6 - Department of Materials Engineering, Sav.C., Islamic Azad University, Saveh, Iran

Received: 2025-07-29 Accepted : 2025-09-09 Published : 2025-06-08

Keywords: Austempered ductile iron, ausferrite, austempering, two-step austempering, tensile strength, copper addition,

Abstract :

This study investigated the influence of copper addition and two-step austempering temperature on the microstructure, phase fractions, and mechanical properties of austempered ductile iron (ADI). Two alloys, one without copper and one containing 1.5 wt% copper, were melted and cast. Samples were austenitized at 900°C for 90 minutes, quenched to 260°C, and held for 5 minutes. They were subsequently austempered at either 350°C or 400°C for 120 minutes and then air-cooled to room temperature. Characterization was performed using tensile testing, hardness measurements, optical metallography, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Tensile and hardness test results indicated that increasing the two-step austempering temperature decreased yield strength, ultimate tensile strength, elongation, hardness, and retained austenite content. The addition of copper enhanced all measured mechanical properties compared to the copper-free samples.The addition of copper enhanced all measured mechanical properties compared to the copper-free samples.

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