Typical Microstructures of Iron-Base Alloys

Abstract

This article is a pictorial representation of commonly observed microstructures in iron-base alloys (carbon and alloy steels, cast irons, tool steels, and stainless steels) that occur as a result of variations in chemical analysis and processing. It reviews a wide range of common and complex mixtures of constituents (single or combination of two phases) that are encountered in iron-base alloys and the complex structure that is observed in these microstructures. The single-phase constituents discussed in the article include austenite, ferrite, delta ferrite, cementite, various alloy carbides, graphite, martensite, and a variety of intermetallic phases, nitrides, and nonmetallic inclusions. The article further describes the two-phase constituents including, tempered martensite, pearlite, and bainite and nonmetallic inclusions in steel that consist of two or more phases.

Etching technique for revealing work hardening regions in Mg–9Al–1Zn alloy

“…acetic picral, 9 g picric acid, 30 mL acetic acid, 150 mL ethyl alcohol and 20 mL H 2 O. 15,21 The reason for selecting the etching solution is that acetic picral solution could reveal the deformation zone, such as cold work and twining, as described in the literature review.…”

“…To understand the plastic deformation characteristics, the deformation zone can be investigated by several experimental and numerical approaches, such as etching techniques, photoelastic stress analysis, microhardness measurements and finite element analysis (FEA). [5][6][7][8][9][10][11][12][13][14][15] The etching technique would be a reasonable approach for the revelation of the plastic deformation zone because of low cost and simplicity. There are several etching techniques which have been proposed that use the detection of microstructure and dislocation density in the plastic deformation zone.…”

“…There are many etching solutions to observe the microstructural morphology in Mg alloys: 15 as follows: AZ91 (tensile strength s UTS 5126 MPa and 0?2% proof strength s 0?2 569 MPa) and AZ31 (s UTS 5216 MPa and s 0?2 5108 MPa). A severe plastic deformation in each specimen was introduced by imposing a hardened carbon steel wire (550 HV) with a compressive force of 3430 N at a loading rate of 1 mm min 21 .…”

“…There are many etching solutions to observe the microstructural morphology in Mg alloys: 15 nital, glycol, acetic glycol, hydrofluoric acid (HF), phosphor picral and acetic picral. The nital etchant shows general microstructure of Mg alloy.…”