Superplastic behavior of two ultrahigh boron steels

Journal Article · Wed Jun 01 00:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02652298· OSTI ID:7175288

Jimenez, J A ^[1]; Gonzalez-Doncel, G; Ruano, O A ^[2]; Acosta, P ^[3]

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1. Max Planck Inst. fuer Eisenforschung, Duesseldorf (Germany)
2. C.S.I.C., Madrid (Spain). Centro Nacional de Investigaciones Metalurgicas
3. Krupp VDM, Altena (Germany)

The high-temperature deformation behavior of two ultrahigh boron steels containing 2.2 pct and 4.9 pct B was investigated. Both alloys were processed via powder metallurgy involving gas atomization and hot isostatic pressing (hipping) at various temperatures. After hipping at 700 C, the Fe-2.2 pct B alloy showed a fine microstructure consisting of 1-[mu]m grains and small elongated borides (less than 1 [mu]m). At 1,100 C, a coarser microstructure with rounded borides was formed. This alloy was superplastic at 850 C with stress exponents of about two and tensile elongations as high as 435 pct. The microstructure of the Fe-4.9 pct B alloy was similar to that of the Fe-2.2 pct B alloy showing, in addition, coarse borides. This alloy also showed low stress exponent values but lacked high tensile elongation (less than 65 pct), which was attributed to the presence of stress accumulation at the interface between the matrix and the large borides. A change in the activation energy value at the [alpha]-[gamma] transformation temperature was seen in the Fe-2.2 pct B alloy. The plastic flow data were in agreement with grain boundary sliding and slip creep models.

• OSTI ID: 7175288
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 25:6; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
DEFORMATION
MICROSTRUCTURE
IRON BASE ALLOYS
EXPERIMENTAL DATA
HOT PRESSING
PLASTICITY
STEELS
ALLOYS
DATA
FABRICATION
INFORMATION
IRON ALLOYS
MATERIALS WORKING
MECHANICAL PROPERTIES
NUMERICAL DATA
PRESSING
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies