Defence Metallurgical Research Laboratory

About: Defence Metallurgical Research Laboratory is a facility organization based out in Hyderabad, India. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 1208 authors who have published 2662 publications receiving 51663 citations.

Evolution of microstructure in laser surface alloying of aluminium with nickel

Abstract: Surface alloying of a commercially pure aluminium with nickel was carried out using a pulsed Nd-YAG laser. The distribution of the alloying element (nickel) in the alloyed layer was found to be highly non-uniform irrespective of the depth of alloying. The microstructure of the alloyed layer was found to consist mainly of a cellular solid solution phase of nickel in aluminium (α-Al), a lamellar eutectic of α-Al and Al 3 Ni phases, and primary Al 3 Ni dendrites. The microstructure of the alloyed layer is explained in terms of inhomogeneity of the nickel distribution. The effects on the microstructure of inherent rapid solidification under the conditions of laser surface alloying were also examined.

The effect of heat treatment and niobium content on the room temperature tensile properties and microstructure of Ti3AlNb alloys

Abstract: The microstructure and room temperature tensile properties of two Ti 3 Al base alloys, Ti-24at.%Al-11 at.%Nb and Ti-24at.%Al-15at.%Nb, were evaluated as a function of cooling rate and aging temperature for β solution treatment, and as a function of solution treatment temperature and aging condition for α 2 + β heat treatments. While both alloys show similar trends of tensile behaviour as a function of heat treatment, the Ti-24Al-15Nb alloy in general possesses better strength and ductility than the Ti-24Al-11Nb alloy.

Effect of tungsten content on microstructure and mechanical properties of swaged tungsten heavy alloys

Abstract: This paper describes the effect of tungsten content on microstructure and mechanical properties of swaged Co-containing tungsten heavy alloys with varying tungsten (90W–7Ni–2Fe–1Co, 93W–4.9Ni–1.4Fe–0.7Co and 95W–3.5Ni–1Fe–0.5Co). With increasing tungsten while tensile strength goes through a maximum, both percent elongation and impact energy decrease. Microstructure and fractographic analyses have been carried out in order to explain the trends in mechanical properties. Predominant transgranular fracture of tungsten grains combined with ductile dimple failure of the matrix in 90% W alloy is responsible for superior properties of this alloy in comparison to the alloy with 95% W. The highest tensile strength attained in 93% W alloy is attributed to predominant cleavage failure of W-grains. The results clearly indicate that the matrix volume fraction, contiguity and matrix mean path greatly influence the mechanical properties of tungsten heavy alloys.