Research

Research Activities

The groups’ broad research interest/area is on “mechanical behaviour of advanced metallic materials in bulk and porous forms”. The main research focus within this is to develop or design new metallic alloy systems through the microstructure – property optimization route for various structural and biological applications. The research groups’ primary aim is two-fold: i) to exploit in situ phase transformations in microstructures, triggered by mechanical and/or thermal means to enhance the mechanical properties; ii) to achieve microstructure modifications through various methods leading to grain refinement, precipitation, phase change (in terms of structure, morphology and fraction), fibrous architecture variation (in porous materials), etc., to accomplish mechanical property improvements.

Within the above theme, groups’ current research activities focus on titanium, high entropy alloys, advanced steels, porous smart materials and auxetic materials/composites involving following aspects:

I. Alloy design through Transformation Induced Plasticity (TRIP)

Recent focus is to improve material properties by triggering stress-induced martensite (SIM) formation upon loading – TRIP effect (in steels). Studies in β titanium (β-Ti) alloys show that SIM transformation in a retained high temperature phase (austenite, β) results in reasonable improvement of strength-ductility properties. Main factors influencing the TRIP effect in β-Ti alloys are martensite start (Ms) temperature and the (meta-) stability of β phase. Hence attempts are being made to establish the Ms dependence with quantified microstructure factors to propose new alloy compositions. Overall plan is to develop an alloy design strategy – for designing new compositions within β-Ti and Fe-based systems – to achieve enhanced properties via TRIP effect.

Current interest is in quantifying the effect of microstructural factors (through SPD processes) on SIM formation using well-known metastable β-Ti and TRIP steel systems.

Microstructure of 3D printed Ti-6Al-4V alloy

II. Microstructure modification in Advanced materials

The microstructure plays an integral role in achieving enhanced properties in metallic materials. Specifically, in critical applications such as power plants, gas turbines etc., where high strength, high ductility and high performance (i.e., thermal stability, withstanding extreme conditions etc.,) are being demanded, the stability of the microstructure and a control on its features are critical. Precipitation, careful heat treatment conditions are the potential ways in which required microstructure for improved properties can be achieved. The overall plan is to quantify the various microstructural parameters to achieve optimum structure-property improvements.

Current interest is in the microstructure modifications of CoCrFeNi-based HEAs, Titanium alloys and welded T91, SS304H or Inconel alloys as power plant materials.

Spherical precipitates in CoCrFeNi-Ti, Al high entropy alloy

III. Design and development of porous smart materials

a. Fibre network materials made of metallic fibres

Current focus is on a new generation of structural and functional porous material, which is developed by metallurgically (sintering) bonding stochastic assemblies of multiple metal fibres, wires or rods at their contact points, often referred to as “fibre networks”. They offer high porosity (up to 95%) and an interesting combination of properties: moderate strength and toughness, good permeability and conductivity. Furthermore, they involve relatively simple and cost-effective production routes (compared to cellular foam structures), offering considerable versatility in metal composition (material and microstructure) and network architecture to tune properties pertaining to practical requirements.

b. Auxetic materials or structures

Auxetic materials (i.e. showing negative Poisson’s ratio (ν)) are associated with enhancement of properties like shear modulus, indentation resistance and impact. Mainly they can exhibit improved fracture toughness, attractive for automotive/aerospace industries. Among many auxetic structures, the re-entrant honeycombs are reported with a limiting ν value of -1. However, the transversely isotropic network structure has no theoretical limit on the negative ν value. Attempts are being made to theoretically establish the elastic properties (Young’s modulus (E) and Poisson’s ratio (ν)) variation in anisotropic crystalline materials of different crystal systems.

Current interest is in stainless steels, SMAs, Ti-, Ni- and Fe- based stochastic fibre network- and auxetic (i.e. negative Poisson’s ratio)- materials or composites.

Research Facilities

Sintering Hot Press Machine


  • Capacity: 200 kN

  • Operating Temperature: 1600°C (Max)

  • Working Atmosphere: Vacuum or any inert atmosphere

  • Ram Speed: 1 – 50 mm/min (in steps of 1)

  • Pressure: 0.1 – 100 bar ( in steps of 0.1)


In-Situ Tensile Stage

  • Maximum applicable load = 5000N

  • Standard speed limits = 0.1 - 63µm/sec.

  • Usable speed limits = 0.5 - 50 µm/sec.



Electrolytic Polishing Machine

Power Supply

50/60Hz (max. load 9.8A) 1 x 100V / 120V 50/60Hz (max. load 4.9A) 1 x 220V / 240V

Output voltage/current

Polishing 0 - 100V (1V steps) / 6A Etching 0 - 25V (0.5 V steps) / 6A

External Etching 0 - 15V (0.5 V steps) / 1.5A