Scope and Objectives

1. To develop online process monitoring and feedback control in laser cladding and additive manufacturing processes; and correlation with micro-structure and mechanical properties for ensuring reproducibility and repeatability . Inconel and Stellite with WC, TiC, WS2 and MoS2 additives and PH1 stainless steel will be used for depositions. 2. To develop laser hybrid powder spray process for micro-structure control in functionally graded deposition. 3. To augment adjustable beam shaping for large surface area coverage in laser cladding. 4. To investigate selective laser sintered / melted specimens behaviour under dynamic mechanical loading. 5. To model thermal history and micro-structure in laser cladding and analyze fatigue behaviour of SLM specimens

Deliverables

1. Online thermal history monitoring and feedback control system for laser cladding and additive manufacturing 2. Adjustable laser beam shaping optical system 3. Laser cladding process with Inconel and Stellite powders and their composites incorporating WC, TIC, TiN etc. for surface hardfacing and refurbishing of engineering parts 4. Laser hybrid cold spray process for controlling micro=structure in metal matrix composites 5. Laser shock peening of laser additive manufactured (LAM) parts for improving mechanical properties 6. Database of mechanical properties of LAM parts under dynamic mechanical loading

Videos

https://youtu.be/M8iF4m_752k

Scientific Output

1. Near real time monitoring of heating and cooling rates and melt pool lifetime in laser cladding and additive manufacturing and correlation with micro=structure and mechanical properties 2. Feedback control for laser cladding and LAM for ensuring reproducibility and repeatability 3. Functionally graded laser deposition with hybrid laser cold powder spray process for improved surface tribological characteristics 4. Laser surface engineering for enhanced surface characteristics through transformation hardening, surface remelting, alloying and cladding with laser beam of different shapes 5. Laser additive manufacturing of simple and complex geometries 6. Determination of fatigue behaviour of SLM specimens under different dynamic loading conditions. 7. Improvement of fatigue life through surface polishing by different conventional and non-conventional methods, such as electro-polishing, laser re-melting and laser shock peening 8. Modeling of laser cladding and additive manufacturing processes

Results and outcome till date

1. Near real time monitoring of heating and cooling rates and melt pool lifetime in laser cladding and additive manufacturing and correlation with microstructure and mechanical properties
2. Feedback control for laser cladding and LAM for ensuring reproducibility and repeatability
3. Functionally graded laser deposition with hybrid laser cold powder spray process for improved surface tribological characteristics
4. Laser surface engineering for enhanced surface characteristics through transformation hardening, surface remelting, alloying and cladding with laser beam of different shapes
5. Laser additive manufacturing of simple and complex geometries
6. Determination of fatigue behaviour of SLM specimens under different dynamic loading conditions.
7. Improvement of fatigue life through surface polishing by different conventional and non-conventional methods, such as electro-polishing, laser re-melting and laser shock peening
8. Modeling of laser cladding and additive manufacturing processes.

Societal benefit and impact anticipated

Additive manufacturing (AM) or 3 D printing is poised to revolutionize the way things are made and supplied. It can make any object through layer-by-layer material deposition from its 3 D CAD model. Any complex shape with varieties of materials can be manufactured without requiring expensive tooling and molds in a relatively short time from design concept-to-market, and importantly is a Green manufacturing process with minimal material waste and reduced carbon footprint. This is already being used to manufacture various aerospace, biomedical, micro- electronics, automobile components and also refurbishing costly engineering parts. The process is most suited for manufacturing customized bio-implants. However, since the process involves layer-by-layer deposition of metal powder fused by laser beam the deposited layers undergo different multiple thermal cycles which tends to make the resulting micro-structure inhomogeneous. Therefore, online monitoring and control of thermal history in laser additive manufacturing is important for ensuring the repeatability and reproducibility of micro-structure which determines the mechanical properties of the part. The main object of the project is to develop online monitoring of thermal history and feedback control in laser cladding and laser additive manufacturing processes, and correlate with micro-structure and mechanical properties for ensuring repeatability. Further, the AM parts are expected to undergo variable amplitude loading over a period of time; therefore, it is necessary to investigate the fatigue life performance of AM parts under variable loading conditions. One of the materials for bio-implants is 15-5 PH steel; therefore the fatigue tests of SLM parts of this material under different dynamic loading conditions will be of direct societal relevance. One of the offshoots of the project is the successful development of stellite-6 cladded H13 steel tool for friction stir welding of materials like Cu-Zr alloys Development of laser beam shaping optics is now being exploited for extended area laser treatment with better uniformity and improved surface properties.

Next steps

1. After successful demonstration of correlation between thermo-cycle and resulting microstructure, phases, and conditions of ceramic particles in metal matrix, the next step is to develop real-time thermo-cycle monitoring using two IR pyrometers in tandem or an oscillating single pyrometer and feedback control 2. Development of a laser additive manufacturing setup based on laser blown powder, employing a 5 axis CNC workstation inside a controlled atmosphere chamber; and implementation of the online process monitoring and feedback control being developed 3. Development of a fluidized powder based powder feeder and a cold spray system, and carrying out laser hybrid cold spray process for controlling micro-structure in metal matrix composites, especially to develop solid lubricious coatings of tungsten disulphide and molybdenum disulphide. 4. Study of high temperature wear and corrosion characteristics of laser cladded and additive manufactured parts. 5. Laser surface hardening and repair of engineering components by powder cladding using laser beam of suitable shapes. 6. Investigating the effect of laser shock peening on improving the mechanical properties of laser additive manufactured parts. 7. Simulation modeling of laser cladding and additive manufacturing process for micro-structure and structural analyses

Publications and reports

Journal publications

1. A study on in-situ synthesis of TiCN metal matrix composite coating on Ti-6Al-4V by laser surface alloying process, Journal of Alloys and Compounds, 810, (2019) 15190
2. Effects of different surface modifications on the fatigue life of selective laser melted 15-5 PH stainless steel, Manufacturing Science and Engineering- A, 762 (2019) 138109.
3. Effects of heat treatment and built-orientations on the fatigue life of selective laser melted 15 - 5 PH stainless steel, Manufacturing Science and Engineering- A, 755 (2019) 235 - 245.
4. In process detection of micro-structure changes in laser cladding of in situ Inconel 718 TiC metal matrix composite coating, J Alloys and Compounds, 740 (2018) 545-558.
5. Investigation on the mode of failures and fatigue life of laser based powder bed fusion produced stainless steel parts under variable amplitude loading conditions, J additive Manufacturing, 25 (2019) 71-83.
6. Effect of tempering on laser remelted AISI H13 tool steel, Surface and Coating Technology, 361 (2019) 136-149. 7. Role of molten pool thermo-cycle in laser surface alloying of AISI 1020 steel with in situ synthesized T iN, Surface and Coating Technology, 362 (2019) 150-166.

Conference publications
1. Effect of laser shock peening on corrosion properties of laser additive manufactured IN718 superalloy presented at The 8th International Congress on Laser Advanced Materials Processing, May 21-24, 2019, Hiroshima, Japan.
2. Effect of heat treatment on impact toughness of selective laser melted stainless steel parts, presented in ASME Int. Conf., College Station, Texas, USA, June 18-22, 2018.
3. Effect of heat treatment on corrosion properties of selective laser melted stainless steel parts, presented in ASME Int. Conf., College Station, Texas, USA, June 18-22, 2018.
4. A study on the influence of shielding gas on TiN decomposition in laser surface alloying, NCAMMM-2018, ISBN- 9789387480568.
5.Effect of laser cladding parameters on clad-track uniformity,NCAMMM-2018, ISBN-9789387480568.
6.A Study towards Online Detection of Evolution of Microstructure in In-Situ and Ex-Situ Processing of TiC Metal Matrix Composite Coating by Laser Cladding Technique, NCAFMPM-2017.
7.Effect of variable amplitude loadings on fatigue life of laser sintered parts, Proceedings of the 39th International MATADOR Conference, Springer (Accepted, forthcoming) -Presented at University of Manchester, UK during 05-07 July, 2017

Patents

Mitigation of cracks in dissimilar metals stainless steel and titanium welding, Patent filling no.: 201931001618 Dated 14/01/2019

Scholars and Project Staff

Muvvala Gopinath- Senior Scientific Officer: from 18/05/2018 till 14/04/2019,PhD: (Part time) from May 2017 till 17/05/2018
Sagar Sarkar- Senior Scientific Officer: from 12/06/2019 till 14/05/2020 (Project completion date); PhD (Part time) from May 2017 till 11/06/2019
Puneeth Thati- SRF: Apr'18-till 14/05/2020 (Project completion date), JRF: Nov'17-Apr'18
Harikrishnan R- JRF: Nov'17-till 14/05/2020 (Project completion date)
Sashi Ranjan- JRF: Nov'17- Mar'18
Bibhu Kalyan Panda-JRF: Sep'19 till 14/05/2020 (Project completion date)
Amlan Mahata- PTA: Nov'17 till 14/05/2020 (Project completion date)
Pravanjan Nayak: PTA: Nov'17-Apr'19.

Challenges faced

Delay in fund release for the financial year 2018-19.

Other information

Timely release of funds suggested