Residual stress and cracking in expanded austenite layers
| Autor: | K T Short, D Hoeft, B A Latella |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Journal of Physics: Condensed Matter. 17:3547-3558 |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/17/23/007 |
| Popis: | The residual stress state and mechanical properties of an expanded austenite layer produced by plasma immersion ion implantation (PI3) on type 316 austenitic stainless steel substrates at different temperatures were investigated. Residual stress data were obtained using the substrate curvature technique for six different treatment temperatures in the range 360–520 °C. Lattice expansion, nitrogen concentration with depth and mechanical properties of the layer were investigated using x-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDOES) and nano-indentation, respectively. Layer strength and fracture toughness behaviour were investigated using tensile testing with optical microscopy to study the cracking evolution in situ. The results showed that for the treatments at 360–420 °C lattice expansions greater than 8% were achieved with nitrogen concentrations near 40 at.%. Two distinct stress–temperature regions were identified from the curvature measurements: (i) for treatment temperatures less than 450 °C, high compressive residual stresses in the range 2–3 GPa were found and the fracture resistances of these layers were less than 7 MPa m1/2, and (ii) for treatment temperatures above 450 °C, the residual stress was significantly lower (≈0.7 GPa) but remained constant and the fracture toughness of the layer was improved by a factor of two. |
| Databáze: | OpenAIRE |
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