The ever-growing and constantly evolving field of additive manufacturing is expected to lay a strong foundation for enhancing metal 3D printing capabilities, while making it accessible to the masses by reducing cost and complexity.

Pavan Kumar Ajjarapu, our next pathbreaker, PhD Candidate at the University of Louisville (UofL), researches Additive Manufacturing technologies for fabricating metal and ceramic parts.

Pavan talks to Shyam Krishnamurthy from The Interview Portal about his internship on Shape Memory alloys at BARC, and their applications in contemporary supersonic combat aircrafts that gave him an understanding of the endless possibilities for innovation using materials.

For students, focus on getting a good foundation through your undergraduate programs and explore pursuing internships and small research projects which will greatly help in getting a flavor of different worlds before making a career choice.

Pavan, can you take us through your initial years?

I was born in Rajahmundry, a city by the banks of river Godavari in South India and spent all of my childhood in Visakhapatnam, Andhra Pradesh where I completed schooling and pre-university. My parents are both physicians – my father specializes in Ayurvedic and my mother in Homeopathic Medicine and Surgery. Together, they run a general medicine clinic in the city. Additionally, my mother has been actively involved in philanthropic and charitable drives to provide healthcare access to the economically less fortunate. My sibling followed my parents’ footsteps and is working towards a degree in medicine.

I grew up in a household that was deeply centered on values, hard work and giving back to the community. We were encouraged to be inquisitive, explore and experiment since we were young.  My school was unique in giving us the opportunity to explore life beyond school. I remember returning from school late afternoon and completing schoolwork by 5 pm to have the evening for myself. Be it karate, drawing, singing, badminton, or swimming, the goal was to have fun and learn a skill that came with many learnings along the way. I believe life “on-field” built my personality more than “in-class”. Pushing myself to the limit in the last 200m for a podium finish in the 1500m race or working together as a team and to win the intra-mural Kho-Kho competition will be memories I will always cherish.

I vividly remember wanting to be a scientist as a kid, while witnessing the advent of new equipment and materials that changed the lives of people forever. Later at the age of 16, I was greatly inspired by innovations in manufacturing and the automobile industry. Visakhapatnam is known for its steel plant, and I was in awe of the large-scale manufacturing of iron and steel, from huge blast furnaces to rolling mills. I came to understand I was inspired by “innovation”, its tangible impact, and its ability to change lives for the greater good. 

What did you do for graduation/post-graduation?

I graduated with a B.Tech in Metallurgy and Materials Engineering from Visvesvaraya National Institute of Technology, Nagpur and later moved to University of Cincinnati to pursue a Master’s in Materials Science and Engineering. During this time, I worked on an NSF-funded project for 3D-printing Ni-TiC cermet scaffolds using particle-based liquid inks. Cermet scaffolds have combined advantageous properties of both metals and ceramics & have a variety of significant applications in tech products, from batteries to biomedical implants due to their low density and high surface area. I studied their sintering behavior as a function of time, temperature, and atmospheric conditions to gather preliminary results required to print these cermet scaffolds using particles-based liquids via extrusion which will lay the foundation for future research in this area.

Naturally, to further learn and grow as a researcher, I decided to pursue a PhD. I am currently pursuing my PhD from the University of Louisville in Mechanical Engineering.  My research focuses on processing and fabricating non-ferrous metal alloy components using filament-based Materials Extrusion (MEX) 3D printing. Additionally, I design and process multi-layer filament structures to improve print speed and filament properties, which will assist new material development and innovation in 3D printing.

What were some of the influences that led you to such an offbeat, unconventional and unique career?

Growing up with interests in innovation & research, and being passionate about technological innovations, I was drawn towards choosing an engineering degree. Dr. Ballal’s course: Introduction to Materials Science and Engineering during my undergraduate program acted as a catalyst in choosing Materials Science and Engineering as my major. Furthermore, my short stint as an intern at the Visakhapatnam steel plant gave me an understanding of the field, and the endless possibilities for innovation using materials. 

As I transitioned into my master’s program, I was looking to pursue research and choosing a mentor. I came across my advisor Dr. Ashley and her lab’s work in phase transformations, diffusion and 3D printing materials through a course. I was very interested in the research topic and inspired by Dr. Ashley’s dynamic personality and futuristic impact of her research.

Further in my career, I continued to foster my interests in additive manufacturing technologies and joined the research group of Dr. Kate and Dr. Atre at UofL who primarily work on advanced manufacturing & 3D printing using innovative materials, processing technologies, and design. My mentors have been a constant source of support as I transform into a knowledgeable researcher learning from the wins and falls in research.

How did you plan the steps to get into the career you wanted? Or how did you make a transition to a new career? Tell us about your career path

Coming from a family where both my parents were in healthcare, my career plan was to pursue medicine or related fields. But with an interest in engineering, I came to realize a materials engineer is not so different from a doctor. A doctor studies the results from various tests to determine the “cause of failure” and makes changes at the cellular level to obtain better properties and performance in a human body. Likewise, a Materials Engineer does the same on an atomistic level to bring changes in the properties and performance of the material on a macro-scale. 

During my undergraduate studies in India, I was fortunate to have had the opportunity to work at various national laboratories and industries. I worked as a research intern at the Bhabha Atomic Research Center (BARC), Mumbai and also worked as an industrial trainee at the Vizag Steel Plant. 

My internship at BARC during the summer break after my sophomore year, provided me with the perfect opportunity to understand real-world applications of the theoretical education in my undergraduation. 

I worked on Shape Memory alloys that were intended to be a part of India’s first Light Combat Aircraft: TEJAS, which is the lightest in its class of contemporary supersonic combat aircrafts. As a part of this project, we processed strips of Ni(51)-Ti alloy by vacuum arc melting, forging and rolling, followed by characterizing the samples. I was inspired by the tangible impacts of fundamental concepts I studied in my courses to fabricate and process high-performance functional materials. Realizing that the first Tejas squadron became operational in 2016 (a year after my internship at BARC), I am immensely proud to have had the opportunity of working alongside scientists and researchers who made this possible.

During my MS research, I had the opportunity to work at the Argonne National Laboratory for a very brief period. I assisted a PhD candidate with his research on X-ray computed tomography, while closely looking at the research trajectory in labs. 

Through these opportunities, I met fellow researchers and academicians working on important problems in my field that helped me build a strong network. I have always liked to explore and bring myself up to speed on new techniques or train on new equipment in my research area. I also read literature on research developments that have an impact on the community. I have worked to be a part of numerous initiatives geared towards a similar goal. 

How did you get your first break?

My first exposure to actual research using materials was during my master’s program. Having had educational background in Metallurgy and Materials Engineering, I should say, my first break at utilizing my skills and growing as a researcher was when I joined Dr. Ashley’s lab at the University of Cincinnati. During a time when Additive Manufacturing and 3D printing were still evolving, I was fortunate enough to be working in a lab which specialized in applying Materials Science concepts (such as Kirkerndall effect and pack cementation) in conjunction with 3D printing. Additionally, the idea of developing innovative additive manufacturing technologies from lab scale to pilot scale for niche applications was exciting to say the least.

What were some of the challenges you faced? How did you address them?

To start with, it is popular opinion among the masses (especially in India) that a degree in Metallurgy and Material Science is not a sustainable career choice. I was faced with a similar dilemma while choosing this major against other cliché options. However, I believe this is primarily due to lack of resources available to understand the future career aspects of this field. With a strong interest in this field, I approached alumni of my major from my undergraduate university to understand the various opportunities available to pursue after my graduation. This helped me understand various possibilities of this field and I decided to gain insight and experience at industries via internships.

I was also at cross-roads after the completion of my undergraduate degree. I was excited to pursue a higher degree at certain universities with coursework that catered to my interests. Pursuing this opportunity meant a considerable financial expense and letting go of a job offer at the time. Choosing the latter also meant it was possible I might not be able to pursue research full time.  After a lot of thought and gathering information on two options, I applied to universities that had relevant coursework with scholarship programs for international students. I received an admission from one of them with a Graduate Student Scholarship that made it affordable for me to pursue higher education.

Cut to my life as a research student, I am faced with numerous scientific challenges every day. Learning cannot be complete without making mistakes. I believe failures are extremely important since it instills in us lessons that help in achieving success along the way. 

Where do you work now? Tell us about your current role

I am a Graduate Research Assistant at the University of Louisville (UofL), where I am working towards my PhD in Mechanical Engineering while assisting my advisor on various research projects. My research is broadly focused on Additive Manufacturing of non-ferrous metals, ceramics, and polymer composites. I am trained on multiple AM technologies such as FDM, DLP, and PBF. However, I spend most of my time developing the filament-based Material Extrusion (MEX) 3D printing technology for fabricating metal and ceramic parts.

What I love about my job is the opportunities it provides to think innovatively and work with inter-disciplinary people as a team, while solving problems. In the past, I was awarded the MIMA graduate student grant to attend the Metal Injection Molding conference, and the NSF Student Grant to attend the Additive Manufacturing and Powder Metallurgy conference.

How does your work benefit society? 

My current work in Additive Manufacturing focuses not just on part fabrication or prototyping, but is also geared towards addressing the high costs and logistic challenges involved with 3D printing metals and ceramics. With the right resources, expertise, and a vision, I am currently working towards developing the Material Extrusion (MEX) based technology for fabricating objects in terrestrial as well as extra-terrestrial environments. With evolving and ever-growing additive manufacturing technologies, my research is expected to lay the foundation for enhancing metal 3D printing capabilities, while making it accessible to the masses by reducing cost and complexity.

The design freedom and versatility that extrusion-based 3D printing offers, helps me put my thinking hat on and apply the technology in a multitude of innovative ways. Copper heat sinks for example, especially for electronic applications, are typically manufactured using conventional techniques such as bonding, forging, folding, skiving, or machining. Such heat sinks tend to have simple fin/pin structures, partly attributed to the limitations of conventional processing technologies. In my current work, we are utilizing topology optimization to overcome challenges in transforming this decade-old traditional heatsink design using the sinter-based material extrusion (MEX) 3D printing process.

Furthermore, I am very fortunate to work with the Minority Business Development Agency (MBDA) as a part of an initiative by the Department of Commerce, towards helping minority-owned business enterprises through the Advanced Manufacturing Center in Kentucky.

Tell us an example of a specific memorable work you did that is very close to you!

Quite recently, my colleague and I started working on incorporating bio-based soybean resins for applications in the construction industry, which is heavily reliant on petroleum-based resins in the current time. Not only are these bio-based resins cheaper but they have also been known to be environment friendly. Moreover, COVID-19 pandemic along with other unfortunate events in world politics had its effect on the global supply chain, which demands more such sustainable and renewable raw materials.
This work is particularly close to my heart since it has the potential to impact the environment and community in a substantial way. 

Your advice to students based on your experience?

My advice to students would be to focus on getting a good foundation through their undergraduate programs and explore pursuing internships and small research projects during this time. This will greatly help them in getting a flavor of different worlds before making a career choice. Also, it helps them build many inter-personal skills and relationships that will accompany them on their professional journey. There are ample opportunities available for students to pursue in today’s world and I encourage them to seek information without reservations.

Future Plans?

In the future, I hope to continue to be involved in research and development projects that are challenging, yet exciting at the same time. I intend to work in the field of advanced manufacturing and materials innovation, and pursue meaningful research that will create an impact on the society as a whole. Additionally, I hope to give back to the student community by sharing learnings and resources from my experience and help them navigate their journey in higher education and beyond.