Formation and impact of functionally graded buffer layers between martensitic stainless steel and wrought steel substrate by laser metal deposition

As-deposited superconducting Y-Ba-Cu-O films have been grown on stainless steel substrates by the plasma assisted laser deposition technique. Low interfacial diffusion of iron at the 550°C growth temperature enables us to produce superconducting films with critical temperatures up to 83 K and critical currents up to ∼4 × 103 A/cm2 (40 K). Dependence of the superconducting properties of the Y-Ba-Cu-O films on the surface condition of the mirror finished stainless steel substrate has been studied. Critical temperature and critical current of the films have been improved by heat-treating the substrate and incorporating buffer layers. Variation of the critical current with the bend radii of the film is discussed.

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Experimental Study on Laser Metal Deposition of FGMs with Ultrasonic Vibration

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.271-272.131 ◽

2012 ◽

Vol 271-272 ◽

pp. 131-135 ◽

Cited By ~ 3

Author(s):

Lan Yun Qin ◽

Wei Wang ◽

Guang Yang

Keyword(s):

Ultrasonic Vibration ◽

Metal Deposition ◽

Functionally Graded ◽

Laser Metal Deposition ◽

Vibration System ◽

Hard Phase ◽

Graded Materials ◽

Vibration Effect ◽

Distribution Uniformity ◽

Microstructure And Mechanical Property

Referring to the ultrasonic vibration effect on casting, welding and laser cladding, the paper demonstrates the feasibility that it can be also used in Laser Metal Deposition(LMD)of titanium alloy to protect the defects such as crack,pore and oxidation and refine the grain size and improve the distribution uniformity of solidified structure.So the paper applies ultrasonic vibration system to fabricate the functionally graded materials(FGMs) samples and analyses its effect on the specimen microstructure and mechanical property by experiments.The results show that ultrasonic vibration can suppress the formation of pore、refine the grain and make the TiC hard phase more homogeneous in the FGMs parts, which is also indicated by the microhardness tests

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Evaluation of Two Different Energy Inputs for Deposition of Stellite 6 by Laser Cladding on a Martensitic Stainless Steel Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1119.628 ◽

2015 ◽

Vol 1119 ◽

pp. 628-632

Author(s):

Alain Kusmoko ◽

Druce Dunne ◽

Hui Jun Li

Keyword(s):

Stainless Steel ◽

Laser Cladding ◽

Martensitic Stainless Steel ◽

Stainless Steel Substrate ◽

Steel Substrate ◽

Testing Machine ◽

Wear Testing ◽

Chemical Compositions ◽

Stellite 6 ◽

Energy Inputs

Stellite 6 was deposited by laser cladding on a martensitic stainless steel substrate with energy inputs of 1 kW (MSS-1) and 1.8 kW (MSS-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the MSS steel substrate with the lower heat input (MSS-1). Further, the Stellite coating for MSS-1 was significantly harder than that obtained for MSS-1.8. The wear test results indicated that the weight loss for MSS-1 was much lower than for MSS-1.8. It is concluded that the lower hardness of the coating for MSS-1.8, markedly reduced the wear resistance of the Stellite 6 coating.

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Deformation Characteristics and Mechanism of Martensitic Stainless Steel during Thixoforming

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.217-218.195 ◽

2014 ◽

Vol 217-218 ◽

pp. 195-200

Author(s):

Ren Bo Song ◽

Ya Ping Li ◽

Yong Jin Wang ◽

Cui Qing Zhao

Keyword(s):

Stainless Steel ◽

Strain Rate ◽

Deformation Temperature ◽

Martensitic Stainless Steel ◽

Testing Machine ◽

Functionally Graded ◽

Deformation Resistance ◽

Liquid Region ◽

Deformation Characteristics ◽

Semi Solid

Semi-solid billet of 9Cr18 martensitic stainless steel with globular grains was made by a wavelike sloping plate experimental device, and hot compression tests were carried out in the semi-solid state of 9Cr18 semi-solid billet on Gleeble-1500 thermal simulation testing machine at the temperatures of 1250°C ~1300°C and the strain rates of 0.1 s-1~5.0 s-1to investigate the effects of thixoforming parameters on its deformation characteristics and mechanism. According to the true stress-strain curves obtained from the test, the influence of deformation temperature and strain rate on 9Cr18 semi-solid billet deformation resistance was investigated, and the deformation resistance model of specimen with coexistence of solid and liquid phases was established. In this paper, it was found that deformation mechanism changed because of different deformation temperature and strain rate. Dynamic recrystallization occured at 1250°C in different phases separately. So that big fine recrystallized grains were achieved at the soft primary austenite region while small recrystallized grains were achieved at the hard solidified liquid region. The melted metal would be extruded from the centre of the specimen to the free surface completely when the temperature was higher than 1275°C. And then specimen became FGM (functionally graded materials), with phases and properties graded distribution perpendicular to the stress direction. When thixoforming temperature reached 1300 °C, martensitic transformation occurred after rapid cooling. The mathematics models of the relation between stress and temperatures, fraction of solid, deformation rates and deformation degree of 9Cr18 semi-solid billet were regressed and established based on the dates attained from the compression deformation experiments. The R value was 0.991, and the RMSE value was 3.57.

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