Who We Are

We are experts in our field who have performed over 12,000 analyses on products ranging from nuts, bolts, and screws to radiators, valve pins, and various welds for products ranging from beverage containers to gas turbines and everything in between. 

Our knowledge comes from our careers spanning a broad section of industries, allowing us to be authorities in manufacturing processes, product service applications, and materials engineering.  Our experienced engineers hold degrees in Metallurgical and Materials Science.


Tom Tefelske – President

I am the president of Metallurgical Associates, Inc., a company I co-founded in 1994 with the belief we could provide our clients with high quality solutions to their problems in a cost-effective manner. Our belief proved to be correct over the past 28 years.  I enjoy working with all our clients to assist in solving their metallurgical issues, and each day brings new satisfaction in reaching this goal. 

I have over 40 years of industrial experience specializing in failure analysis starting as a staff metallurgist and worked my way up to a senior metallurgist and technical director. I have earned both my Bachelor of Science in Applied Science and Engineering, as well as my Masters of Science degree in Metallurgical Engineering at the University of Wisconsin.    I have also earned 45 credits towards my Ph.D. in Metallurgical Engineering at The Ohio State University.

I have had the privilege to have authored several papers that have been published in academic journals and taught courses on the subjects of Failure Analysis and Liquid Penetrants at several academic institutions in Wisconsin.

In addition to the above, I am also the president of Tee-Squared Services, Inc. and provide laboratory assessment services for A2LA accreditation.

In my spare time, Wendy and I enjoy spending time at our cottage on Okauchee Lake and cruising around on our pontoon boat.  I also enjoy working on and driving my collection of Alfa Romeo’s.


Wendy Tefelske – Vice President

I have been around engineers all my life. My father, Anthony Lange, was the founder of Lange Lift Company in 1934, which was always his dream.

I have owned my own successful Mary Kay distribution business for decades and when the opportunity arose, I encouraged Tom to step out on his own and start his own business. In 1994 Tom co-founded Metallurgical Associates, Inc. and hasn’t looked back since.

While I have the title of vice president, I am not afraid to dig in wherever and whenever help is needed with the business and am willing to wear a variety of hats. I know the demands of running a growing family business, as I have been around entrepreneurial engineers my entire life.

When I am not running errands for the business (I teasingly call myself the Vice-Presidential Gopher), I spend my time with my wonderful husband and children, working with my church and attending Milwaukee Brewer games.


Anthony “Tony” D’Antuono – Senior Engineer

I am the senior engineer at Metallurgical Associates, Inc.  I started with MAI in June of 2012, but prior to that I worked as a Metallurgical Technician at Metaltek International.

Before working as a metallurgical engineer, I was a science teacher in the Mukwonago School District.  This added experience allows me to describe metallurgical functions to any of our clients, even non-metallurgists.  

I earned Bachelor of Science in Physical Science Education from the University of Wisconsin in Eau Claire and then earned my Bachelor of Science in Materials Engineering from the University of Wisconsin in Milwaukee.

After work, I enjoy cooking, golfing and spending time with my lovely wife and energetic son.


Davan Siegfried – Engineer

I am a materials engineer at Metallurgical Associates, Inc., and have been here since 2021.

I have been in the materials engineering field of study for approximately 5 years now, researching various materials and environmental conditions in the chemical and materials engineering worlds. Currently, I am in the Materials Engineering Master’s program studying kinetics in my thesis project.

In my free time I enjoy traveling, the outdoors, and making metal castings.  


Kelly Brown – Lab Supervisor

I have worked in the metals industry for over 30 years. I began my career in the foundry industry and progressed on to materials testing.

I recently have been brought onboard as the laboratory supervisor at Metallurgical Associates. I enjoy putting the pieces together which help explain the story as to why a component has failed.

My pastimes include golf, watching baseball and hockey. I enjoy being with my wife of nearly 30 years, our two wonderful children and beautiful granddaughter.


Thomas Brefka – Intern

I started my education at the MSOE Mechanical Engineering Program and transferred to UWM to obtain my Materials Engineering Degree. I started at MAI last November and really enjoy what I do here.

After work and on weekends, I enjoy reading, playing video games, and golfing.


Ted Plewa – Intern

I have only been with MAI for a couple of months, but really enjoy the family feel of everything here. I am heading off to UW Platteville at the end of summer to pursue my Mechanical Engineering Degree.

Outside of work, I enjoy all kinds of outdoor activities including disc golf.


Deb Minger – Office Manager

I have been in office administration over the course of my career and started working with MAI in February of 2012. 

At MAI, I am the first face you will see when you come to our facility and the last one you see before you leave.  I sit at the front desk and enjoy greeting our clients and providing all the day-to-day office and accounting operations so our engineers and technicians can do what they do best – problem solving for our clients.

Outside of work, I enjoy my time with my husband and our cat and take pleasure in reading, savoring nature and the outdoors, and cheering on the Milwaukee Admirals


Valerie J Young – Vice President of Operations

Most of my career, I have been in the transportation industry and have recently moved into the metallurgical field.  I am the newest to join MAI and am very excited to be here!

My career has been spent in safety, human resources, and operations.  My passions have always been working with people and developing great teams.  I enjoy learning the whys of how things work and educating myself in a variety of interesting topics. 

Outside of work, I love travelling and I am committed to my loving husband, my wonderful family, and my fantastic dogs.