Effect of particle size on thermal residual stress in WC–Co composites

Coats, D.L; Krawitz, A.D.

doi:10.1016/s0921-5093(03)00379-4

Cited by 52 publications

(29 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, peak breadths can be affected by (1) elastic strain distribution in the diffracting volume, (2) dislocations due to cold work, and (3) size effects due to very small diffracting regions. In the present case, as in previous work in such systems, [11][12][13]15,24,31] the primary source of changes in peak breadths is the first one. A hallmark of effect (1) is that it can be reversible, as a result of reverse changes in temperature or applied load.…”

Section: E Strain Distributionsupporting

confidence: 52%

See 1 more Smart Citation

In-Situ Response of WC-Ni Composites under Compressive Load

Paggett

Krawitz

Drake³

et al. 2007

Metall Mater Trans A

View full text Add to dashboard Cite

The in-situ strain response of WC-Ni cemented carbides (5, 10, and 20 wt pct Ni) to uniaxial compressive load was measured using neutron diffraction. Strain was measured in both phases parallel and transverse to the loading axis of cylindrical samples. Plasticity is observed in the Ni binder from the lowest levels of applied load. The plasticity occurs locally in the Ni phase, on the scale of the microstructure, and leads to continuous curvature of the WC-Ni stress-strain curves and significant toughness of the material. The plasticity results from the interaction of the thermal residual microstresses created during sample production with the applied macrostress. It also leads to anisotropic relaxation of the initial residual stress and the creation of a residual stress state with cylindrical symmetry in the material. This process was observed over three loadunload cycles. Analysis enables phase-specific stress strain curves to be constructed. Finally, strain distributions were observed through peak breadth responses.

show abstract

Section: E Strain Distributionsupporting

confidence: 52%

“…[25,26] It has been shown that the TRS is a strong function of WC particle size, for fixed composition and processing. [24] As the particle size becomes finer, the binder constraint increases resulting in higher mean TRS values.…”

Section: A Initial Trsmentioning

confidence: 99%

In-Situ Response of WC-Ni Composites under Compressive Load

Paggett

Krawitz

Drake³

et al. 2007

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…This effect is attributed to the higher surface area to particle volume ratio of smaller particles, resulting in changes in the pore and intersplat morphology, which resists stress relaxation in the deposited layer. In the investigation by Coats et al [7] on WC-Co coatings, it was concluded that with the increase in powder particle size the tensile stress in the Co and the compressive stress in the WC decreased. In the current investigation, a similar trend can be observed for the compressive residual strain in the HVOF coating, although the tensile residual strain is lower for the finer powder HVOF coating.…”

Section: Coating Microstructurementioning

confidence: 98%

“…The peening effect in HVOF process is understood to cause compressive residual stress in thermal spray coatings. Similarly, investigations relating to the influence of powder particle size on the residual stress of thermal spray coatings have indicated that the decrease in powder particle size increases the residual stress in thermal spray deposits [7][8]. This effect is attributed to the higher surface area to particle volume ratio of smaller particles, resulting in changes in the pore and intersplat morphology, which resists stress relaxation in the deposited layer.…”

Section: Coating Microstructurementioning

confidence: 99%

Neutron diffraction residual strain measurements in alumina coatings deposited via APS and HVOF techniques

Ahmed

Faisal

Reuben

et al. 2010

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Abstract. Residual strains in air plasma sprayed (APS) and high velocity oxy-fuel (HVOF) alumina (Al 2 O 3 ) coatings were investigated by means of neutron diffraction technique. Results of this investigation conclude that through thickness residual strain in the APS coating was mainly tensile whereas the HVOF coating had both compressive and tensile residual strain. Further analysis of Vickers indentation fracture behaviour using acoustic emission (AE) technique concluded that the nature and magnitude of these residual strain fields had a direct effect on the fracture response of two coatings during the indentation process. IntroductionThermally sprayed alumina (Al 2 O 3 ) coatings are used in industry for thermal and electrical resistance applications. Measurement of residual strains in these coatings is critical for modeling and designing improved components. Non-destructive through thickness residual strain measurements in thermal spray coatings is possible via the high penetration depth achieved by the neutron diffraction technique [1][2]. The influence of coating process parameters on the residual stress fields of Al 2 O 3 coatings has been a topic of research of previous investigations [3]. Recent advancements in high velocity oxy-fuel (HVOF) technique has made it possible to deposit much finer alumina powders at relatively lower temperatures than those achieved by air plasma spraying (APS) process [4]. This has the effect of limiting phase transformations during coating deposition, which along with the relatively higher velocity and lower temperature of HVOF process can influence residual stress behavior. This paper therefore aims to investigate the through thickness changes in the residual strain profile of finer powder and conventional Al 2 O 3 coatings deposited by the HVOF and APS processes, respectively. Further analysis interlinking fracture behavior and residual strain is also presented.

show abstract

“…It is well known that despite the carbide phase is under compressive RTS on average, the actual local stress can vary in a rather wide range and even become tensile on some small fraction of instances of the carbide crystals in cemented carbides (Coats & Krawitz, 2003;Krawitz, Crapenhoft, Reichel, & Warren, 1988;Krawitz, Reichel, & Hitterman, 1989;Weisbrook & Krawitz, 1996). The RTS is added to the tensile and shear stress field of the crack (Cutler & Virkar, 1985;Rice, 1983) that creates a combined stress field of the crack and RTS and, by these means, affects the location of the weakest carbide region.…”

Section: Step Onedcarbide Phase Precrackingmentioning

confidence: 99%