OS19-4-7 The Effect of Stress State on High Temperature Tensile Deformation of Fine-Grained Mg-3Al-1Zn Alloy Sheet

The paper is devoted to an experimental investigation of a high-temperature deformation in V-alloyed high-nitrogen austenitic Fe-19Cr-22Mn-1.5V-0.3C-0.6N steel processed via different thermo-mechanical treatments. Simple thermo-mechanical processing regimes (cold rolling or rolling with single post-deformation anneal) do not allow to realize a substantial elongation in high-nitrogen steel during high-temperature tensile tests. For fine-grained austenitic structure with an average grain size of 3 µm, the maximal value of elongation to failure of 150% was realized at temperature 950 °C. Using a multi-stage thermo-mechanical treatment included cold rolling and intermediate anneals, a heterophase grain/subgrain structure with high density of deformation-induced defects and precipitates was produced. When heated to a deformation temperature, this deformation-assisted microstructure recrystallizes into a stable fine-grained structure and demonstrates the attributes of superplastic flow (values of elongation to failure higher than 400%) in the temperature range of 850-1000 °C. The maximum elongation of 900% is achieved at temperature of 950 °C and an initial strain rate of 10-4 s-1.

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High temperature tensile properties and their application to toughness enhancement in ultra-fine grained W-(0-1.5)wt% TiC

Journal of Nuclear Materials ◽

10.1016/j.jnucmat.2008.12.181 ◽

2009 ◽

Vol 386-388 ◽

pp. 579-582 ◽

Cited By ~ 39

Author(s):

H. Kurishita ◽

S. Matsuo ◽

H. Arakawa ◽

M. Narui ◽

M. Yamazaki ◽

...

Keyword(s):

High Temperature ◽

Tensile Properties ◽

Fine Grained ◽

High Temperature Tensile ◽

Toughness Enhancement ◽

High Temperature Tensile Properties

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Experimental Study and Numerical Simulation of the Tensile Test for GH4169 Coated with YSZ Coating at High Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.782.237 ◽

2015 ◽

Vol 782 ◽

pp. 237-244

Author(s):

Lin Lin Wang ◽

Qun Bo Fan ◽

Hong Mei Zhang ◽

Fu Chi Wang

Keyword(s):

High Temperature ◽

Tensile Test ◽

Tensile Deformation ◽

Axial Stress ◽

Simulation Method ◽

Metal Substrate ◽

Transitional Region ◽

Failure Initiation ◽

Ysz Coating ◽

High Temperature Tensile

In this study, high temperature tensile test was conducted on the specimen of superalloy GH4169 coated with wt8%-YSZ under the conditions of 950°C and 80MPa. By using finite element (FE) simulation method, the failure initiation and evolution of the metal substrate and YSZ coating were predicted. It was found that stress concentration originally occurred in the YSZ ceramic top coating, causing an axial stress and triggering severe debonding failure in the center region of the specimen at t=180s. With increased load, further interfacial debonding failure of the residual coating occurred due to the presence of oblique tensile stress and at t=900s, and only a few residues can be seen at the arc transitional region. Subsequently, the metal substrate was subjected to uniform tensile deformation and finally ruptured at t=76min with apparent necking. In addition, it was notable that YSZ coating can relieve stress significantly (nearly 40% lower), thus helping prolong the substrate's service life in the same environment. Simulated results were consistent with observed behavior.

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