Characterization of laser produced molybdenum surface alloys on stainless substrates

Journal Article · · Journal of Laser Applications; (United States)

DOI:https://doi.org/10.2351/1.4745327· OSTI ID:5633190

Kumar, D; Biswas, A R; Goswami, G L ^[1]; Sridhar, K; Deshmukh, M B ^[2]

---

1. B.A.R.C., Bombay (India)
2. Naval Chemical and Metallurgical Lab., Bombay (India)

High Mo surface alloys on stainless steels 304L and 316L were produced by laser surface alloying. For this, a layer of 60 [mu]m thickness was overlaid on the substrates by plasma spraying of Mo powders. These were further treated by a Nd:YAG pulsed laser for alloying. Depths of alloying in the range of 440-1110 [mu]m were achieved. Concentration in the range of 5.2-15.0 wt% Mo within the laser alloyed zone was, in general, uniform throughout. During alloying, in-situ heating at 700C was required to prevent cracking in samples with 5.2-6.0 wt% Mo. Higher Mo content enhanced the cracking tendency and made it difficult to prevent cracking completely even at this temperature. Fully austenitic microstructure of the substrate metals transformed to austenitic-ferritic duplex for 5.2-9.0 wt% Mo and to fully ferritic for 15.0 wt% Mo. Primary solidification mode also changed to FA, FA + F and finally to F depending upon Mo content in the alloyed zone. Ferrite content in the alloyed zone was in the range of 31-79% depending upon amount of Mo. Microhardness was increased from 173 VHN for 316L to 198-790 VHN depending upon wt% Mo in the alloyed zone. Preliminary studies indicated that pitting potential in 3.5% NaCl aqueous solution improved substantially from 132 mV for 304L and 240 mV for 316L to 480 mV and 500 mV respectively for 5.5-6.0 wt% Mo in the alloyed zone.

• OSTI ID: 5633190
• Journal Information: Journal of Laser Applications; (United States), Journal Name: Journal of Laser Applications; (United States) Vol. 5:2/3; ISSN 1042-346X; ISSN JLAPEN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360102 -- Metals & Alloys-- Structure & Phase Studies
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
AUSTENITIC STEELS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM-NICKEL STEELS
CHROMIUM-NICKEL-MOLYBDENUM STEELS
CORROSION
CORROSION RESISTANT ALLOYS
DATA
DEPOSITION
EXPERIMENTAL DATA
FABRICATION
HEAT RES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
LASERS
LOW CA
MATERIALS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NEODYMIUM LASERS
NICKEL ALLOYS
NUMERICAL DATA
PHASE TRANSFORMATIONS
PITTING CORROSION
PLASMA ARC SPRAYING
SOLID STATE LASERS
SOLIDIFICATION
SPRAY COATING
STAINLESS STEEL-304L
STAINLESS STEEL-316L
STAINLESS STEELS
STEEL-CR17NI12MO3-L
STEEL-CR19NI10-L
STEELS
SURFACE COATING