This dataset contains the information on our recent body of work on Ag-induced transformation of FeMn alloys and all the relevant data files. In this work, attempt to explain the austenite-martensite phase transformation occurring in FeMn alloys upon additions of Ag. In the study, a combined experimental and theoretical approach are applied to reveal the mechanism behind the phase transformation. While equiatomic FeMn and FeMn-1Ag alloys possess a fully austenitic structure, a change in the crystallographic structure is observed upon addition of 3 and 5 wt% of Ag, where a mixture of γ austenite and ε martensite phases is observed. Compression tests reveal that such structural transition causes an increase of the yield stress. The evolution of microstructure with the Ag content can be understood from theoretical calculations which show that Ag atoms prefer the intrinsic stacking fault (ISF) sites, revealing lower energy for the ε atomic plane sequence. This causes local depletion of the electronic charge, therefore weakening the interatomic bonds at the ISF plane and facilitating the phase transition. In addition, the total energy difference between the γ and ε phases decreases upon Ag addition. This enables the coexistence of both phases in the sample with 5 wt% Ag. Both experimental and theoretical data agree that the magnetization value gradually increases upon Ag addition. This is due to the local stress that is introduced by Ag atoms, which expand the Ag-Fe and Ag-Mn first neighbour interatomic bonds compared to FeMn. This stress results in electronic charge transfer that locally alters the Fe and Mn atomic magnetic moments.

1. Description of methods used for collection-generation of data: Various experimental tools were employed in this line of work, such as X-ray diffraction and transmission electron microscopy for structural and microstructural inspections, compression tests for evaluation of mechanical properties, vibrating sample magnetometry for characterizing magnetic properties, the Vienna ab initio simulation package (VASP) density functional theory (DFT)for computations. [Silver-induced γ→ε martensitic transformation in FeMn alloys: An experimental and computational study, https://doi.org/10.1016/j.jallcom.2023.171640].

2. Methods for processing the data: The data files can be processed using Origin software, PowerPoint,ImageJ, X’Pert HighScore Plus and DigitalMicrograph.

3. Instrument- or software- specific information needed to interpret the data: For the magnetometry data, any antiferromagnetic signals were subtracted using the VSM software in our lab. The format of this dataset was converted into an open format that can be processed using Origin software. XRD data is presented as an xdrml file, which can be open using X’Pert HighScore Plus software or converted to .txt file.

4. Instruments, calibration and standards information: The VSM magnetometer was calibrated using a standard nickel pallet provided by the company (Micro Sense, LOT, Quantum Design). The compression tests were performed according to DIN 50106:2016–11 with a height (4 mm) to diameter (2 mm) ratio of 2.

5. Environmental or experimental conditions: The measurements were conducted at ambient conditions.

6. Quality-assurance procedures performed on the data: The results were carefully analyzed and interpreted. Peer review process of the corresponding scientific article by experts in this field has been done, and its imminent publication in Journal of Alloys and Compounds is expected.