Thermo-mechanical effects caused by martensite formation in powder metallurgy FeMnSiCrNi shape memory alloys. (8th August 2018)

• Record Type: Journal Article
• Authors: Pricop, Bogdan; Mihalache, Elena; Stoian, George; Borza, Firuța; Özkal, Burak; Bujoreanu, Leandru-Gheorghe
• Is Part Of: Powder metallurgy. Volume 61:Number 4(2018)
• Page Start: 348
• Page End: 356
• Publication Date: 2018-08-08
• Subjects: Shape memory alloys -- mechanical alloying -- solution heat treatment -- martensite -- tensile pre-straining; Powder metallurgy -- Periodicals; 671.3705
• DOI: 10.1080/00325899.2018.1492773
• Languages: English
• ISSNs: 0032-5899

Abstract

ABSTRACT: The paper reports solution treatment (ST) and mechanical alloying (MA) effects on the structure and static/dynamic mechanical behaviour of PM-MA'ed FeMnSiCrNi shape memory alloys associated with the formation of thermally and stress-induced martensite. The specimens were subjected to tensile pre-straining, in order to stress induce martensite and their gauges were cut and prepared for X-ray diffraction (XRD) as well as for optical and scanning electron microscopy (SEM). XRD patterns allowed determining the presence of large amounts of α ′-body centred cubic (bcc) besides ε -hexagonal close packed (hcp) martensite and γ -face centred cubic (fcc) austenite. The decrease in the amount of α ′-bcc at specimens ST'ed at 1273 and 1373 K, with increasing pre-straining degree, was confirmed by XRD patterns and SEM micrographs. Dynamic mechanical analysis (DMA) was performed by strain sweeps (SS). The SS-DMA graphs displayed storage modulus plateaux which were associated with the formation of ε -hcp martensite.