Effect of Sintering Time on the Densification, Microstructure, Weight Loss and Tensile Properties of a Powder Metallurgical Fe-Mn-Si Alloy

Abstract

This work investigated the isothermal holding time dependence of the densification, microstructure, weight loss, and tensile properties of Fe-Mn-Si powder compacts. Elemental Fe, Mn, and Si powder mixtures with a nominal composition of Fe-28Mn-3Si (in weight percent) were ball milled for 5 h and subsequently pressed under a uniaxial pressure of 400 MPa. The compacted Fe-Mn-Si powder mixtures were sintered at 1200 • C for 0, 1, 2, and 3 h, respectively. In general, the density, weight loss, and tensile properties increased with the increase of the isothermal holding time. A significant increase in density, weight loss, and tensile properties occurred in the compacts being isothermally held for 1 h, as compared to those with no isothermal holding. However, further extension of the isothermal holding time (2 and 3 h) only played a limited role in promoting the sintered density and tensile properties. The weight loss of the sintered compacts was mainly caused by the sublimation of Mn in the Mn depletion region on the surface layer of the sintered Fe-Mn-Si compacts. The length of the Mn depletion region increased with the isothermal holding time. A single α-Fe phase was detected on the surface of all of the sintered compacts, and the locations beyond the Mn depletion region were comprised of a dual dominant γ-austenite and minor ε-martensite.

Fabrication and characterization of nanostructured Fe–28Mn–6Si–5Cr shape memory alloy

“…A furnace with a maximum heating capacity of 1600°C was used. The specimens were heated at a temperature of 1200°C for around 4 h with Argon gas shielding (Xu et al, 2017).…”

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

“…When Fe-SMA is employed as a measure of prestressing, the amount of prestress is the property of most concern to engineers. With the aim of increasing the shape recovery properties, many research groups across the world have been devoted to developing improved production and manufacturing processes, including but not limited to thermal mechanical training, adjusting the chemical compositions and heat treatment [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. These efforts greatly enhance the reliability of Fe-SMA as an emerging prestressing strategy.…”

Sub-Microstructure of Surface and Subsurface Layers after Electrical Discharge Machining Structural Materials in Water

“…The studies [2,11,[15][16][17]19,[46][47][48] show that penetration (adsorption in the recast layer) of the tool electrode material components can reach a depth of 10 µm (from 2.55 up to 50 µm depending on used materials of electrodes, dielectric medium, and experiment factors). At the same time, this uneven distribution of the workpiece and wire elements can be explained by sublimation phenomena of the recast layers (similar to laser ablation during heating with the concentrated energy flows such as laser, plasma, electric discharges, fast energy neutral atoms [49][50][51][52]), when components of workpiece material sublimate primarily [53,54]. More refractory components of the secondary material of the second order, such complex compounds as oxides and stoichiometric solid solutions of oxides [29,[55][56][57][58][59], do not entirely sublimate in a single current pulse and remain in the form of a nano scaffold.…”