Graduation 2012

Graduation 2012

WPI's 144th Commencement ceremony was held on the campus Quadrangle, where 718 Bachelor of Science degrees, 340 master's degrees, and 19 PhDs were awarded. Thousands of students, their families and friends, trustees, and other special guests were on hand to experience the inspirational messages delivered by keynote speaker Roger W. Ferguson Jr., president and CEO of TIAA-CREF, and WPI President and CEO Dennis Berkey. This year, Materials Science and Engineering awarded four Doctor of Philosophy degrees and fourteen students received their Master of Science degree.

PhD Graduates

Lance Wu
Mei Yang
Anastasios Gavras
Xiaolan Wang

Master Graduates

Haiyang Zou
Haikun Xu
Stephanie Baldwin
Michael Walker (MPE)
Philip Chan
Yangyang Fan
Adinath Narasgond
Rose Roy
Chen Dai
Yuzhong

Master Graduate Thesis

Development of Aluminium Dross-based Material for Engineering Applications

Authors:
Student:  Chen Dai   Advisors:  Prof. Diran Apelian

Abstract:
Aluminum dross is a by-product of Aluminum production. At present, dross is processed in rotary kilns to recover the Al, and the resultant salt cake is sent to landfills; although it is sealed to prevent from leaching, the potential for leaching exists and could harm the environment as the salt cake contains fluorides and other salts. Furthermore, much energy is consumed to recover the Al from the dross; this is energy that can be saved if the dross could be diverted and utilized as an engineering material. The objective of this work was to eliminate waste and instead utilize the waste in a natural cycle ( closed loop) by using it as an engineered material. Three avenues were invested to utilize the dross: (i) aluminum composites; (ii) high temperature additive for de-sulphurizing of steel slag; (iii) refractory materials. We have found that the use of dross waste to manufacture refractory material has much merit. Mechanical property evaluations revealed the possibility for dross waste to be utilized as filler in concrete, resulting in 25% higher flexural strength and a 5% higher compressive strength compared to pure cement. These results will be presented and discussed. See more...

Precipitation Strengthening of Aluminium by Transition Metal Aluminides

Authors:
Student:Yangyan Fan   Advisors:  Prof. M. Makhlouf

Abstract:
Aluminum-zirconium alloys exhibit superior strength at elevated temperature in comparison to traditional aluminum casting alloys. These alloys are heat-treatable and their strength depends to a large extent on the quenching and aging steps of the heat treatment process. However, measurements show that the critical cooling rate necessary to retain 0.6 wt. pct. zirconium (the minimum amount necessary for significant strengthening) in a super-saturated solid solution with aluminum is 90ºC/s, which is un-attainable with traditional casting processes. On the other hand, the critical cooling rate necessary to retain 0.4 wt. pct vanadium and 0.1 wt. pct. zirconium in a super-saturated solid solution with aluminum is only 40ºC/s; which suggests that substituting vanadium for zirconium significantly decreases the critical cooling rate of the alloy. This is an important finding as it means that, unlike the Al-0.6Zr alloy, the Al-0.4V-0.1Zr alloy may be processed into useful components by traditional high pressure die-casting. Moreover, measurements show that the hardness of the Al-0.4V-0.1Zr alloy increases upon aging at 400ºC and does not degrade even after holding the alloy at 300ºC for 100 hours. Also, measurements of the tensile yield strength of the Al-0.4V-0.1Zr alloy at 300ºC show that it is about 3 times higher than that of pure aluminum. This increase in hardness and strength is attributed to precipitation of Al3(Zr,V) particles. Examination of these particles with high resolution transmission electron microscopy (HRTEM) and conventional TEM show that vanadium co-precipitates with zirconium and aluminum and forms spherical particles that have the L12 crystal structure. It also shows that the crystallographic misfit between the precipitate particles and the aluminum matrix is almost eliminated by introducing vanadium into the Al3Zr precipitate and that the mean radius of the Al3(Zr,V) particles is in the range from 1nm to 7nm depending on the alloy composition and aging practice. Finally, it is found that adding small amounts of silicon to the Al-0.4V-0.1Zr alloy effectively accelerates formation of the Al3(Zr,V) precipitate. See more...

Synthesis and Characterization of Nanostructured Carbon Supported Pt-based Electrocatalysts

Authors:
Student:  Xi Geng   Advisors:  Prof. Jianyu Liang

Abstract:
Fuel cell, as an alternative green power source for automobiles and portable electronics, has attracted worldwide attention due to its desirable properties such as high energy density and low greenhouse gas emission. Despite great progress in the past decades, several challenges still remain as obstacles for the large-scale commercialization. Among them, the high cost of Pt-based electrode material is considered as a major barrier, while the life span or stability of electrode catalysts is another concern since the electrocatalysts can be easily poisoned during the fuel cell operation. In order to overcome these issues, nanostructured carbon materials, especially carbon nanotubes (CNTs), are studied as catalyst support. In addition, recent research also suggests that the coupling of a second metal element with Pt can effectively protect the electrocatalysts from being poisoned and thus improve their long-term durability.

The objective of the present work was to demonstrate an efficient synthetic method for the preparation of CNTs supported binary PtM (M=Ru, Sn) electrocatalysts. In this project, a polymer wrapping technique along with an in-situ polyol reduction strategy was adopted to decorate well-dispersed binary PtM nanoparticles on the surface of modified-CNTs. The unique nanostructures as well as the excellent catalytic activities of the as-prepared nanohybirds were investigated through a diversity of physiochemical and electrochemical characterization techniques. This fabrication method provided a simple and convenient route to assemble Pt-based catalyst on carbon substrates, which is useful for the further development of high-performance fuel cell catalysts. See more...

Development of a recycling process for Li-ion batteries

Authors:
Student: Haiyang Zou  Advisors:  Prof. Diran Apelian, Prof.Yan Wang

Abstract:
The rechargeable secondary Lithium ion (Li-ion) battery is expected to grow to more than $6.3 billion by 2012 from ~$4.6 billion in 2006. With the development of personnel electronics, hybrid and electric vehicles, Li-ion batteries will be more in demand. However, Li-ion batteries are not widely recycled because it is not economically justifiable (in contrast, at present more than 97% Lead-acid batteries are recycled). So far, no commercial methods are available to recycle different chemical Li-ion batteries economically and efficiently. Considering our limited resources, environmental impact, and national security, Li-ion batteries must be recycled. A new methodology with low temperature and high efficiency is proposed in order to recycle Li-ion batteries economically and with industrial viability. The separation and synthesis of cathode materials (most valuable in Li-ion batteries) from recycled components are the main focus of the proposed research. The analytical results showed that the recycling process is practical and has high recovery efficiency, create great commercial value as well. See more...

PhD Dissertations

Fatigue Crack Growth in Structural Materials: Microstructural Mechanisms and Integrated Design Methods

Authors:
Student:  Anastasios Gavras   Advisors:  Prof. Diana Lados

Abstract:
Fatigue is responsible for the vast majority of failures in most engineering components, either as a result of pure mechanical loading or in conjunction with other phenomena (e.g. corrosion, creep, friction). Traditionally, design against fatigue was based on the “Safe Life” approach. However, this approach is significantly affected by variations in the material’s surface conditions or defect distributions, and the contributions of fatigue crack initiation and propagation cannot be individually understood and partitioned. Most importantly, in the presence of pre-existing flaws, the “Safe Life” approach often overestimates the fatigue life of the component.

In this work, the “Defect Tolerant” approach was used, with focus on both early and advanced stages of crack propagation. The effects of the initial flaw size and material’s microstructure on the fatigue crack growth response were studied, and fatigue crack growth mechanisms at the microstructural scale of various structural materials were identified for different loading conditions. A new model that predicts the response of microstructurally small fatigue cracks was developed. An integrated methodology that incorporates materials characteristics and loading conditions into materials and structural design and fatigue life predictions was also established. These advancements will be presented, and their importance will be discussed in the context of actual applications

Activated Atmosphere Nitriding, Nitrocarburizing and Carburizing Treatments of Carbon, Alloy and Austentic Stainless Steel

Authors:
Student:  Xiaolan Wang  Advisors:  Prof. Richard Sisson, Jr.

Abstract:
In this research, a nitrogen-hydrocarbon gas mixture was used as the process atmosphere for carburizing. It can offer a cost and part quality alternative to the conventional endothermic atmosphere and vacuum processes. It can hold the promise for matching the quality of work parts processed in vacuum furnace, i.e. eliminating the intergranular oxidation in the endogas atmospheres. The process control of nitrogen-hydrocarbon atmosphere is also investigated in the reasearch. For nitriding, hydrocarbon gas addition to the nitriding atmosphere and electric arc discharge activation of the gas on the kinetics of the nitriding process was investigated. Prior to and during the nitriding, hydrocarbon gases were reacted with metal surface and removed oxidation layers, which can accelerate nitriding process. Gas stream-activating, cold-plasma injectors developed at Air Products is also used in these experiments.

The main objective of this project is to develop the conventional, atmospheric-pressure, low-cost surface hardening treatments for the case hardening of carbon, alloy and stainless steel. The possibility of plasma activation of atmosphere and metal surface to accelerate processing time and save energy and time is investigated in this research. The process atmosphere is safer, more efficient, less toxic and less flammable. Process control method for carburizing is also investigated. With minimum modification, commercially available equipment or sensors can be used to monitor non-equilibrium process atmosphere.

Predicting the Response of Aluminum Casting Alloys to Heat Treatment

Authors:
Student: Chang-Kai Wu   Advisors:  Prof. Makhlouf Makhlouf

Abstract:
The objective of this research was to develop and verify a mathematical and the necessary material database that allow predicting physical and material property changes that occur in aluminum casting alloys in response to precipitation-hardening heat treatment. The model accounts for all three stages of the typical precipitation hardening heat treatment; i.e., the solutionizing, quenching, and aging stages; and it allows predicting the local hardness and tensile strength, and the local residual stresses, distortion and dimensional changes that develop in the casting during each stage of the heat treatment process.

The model uses the commercially available finite element softwares and an extensive database that was developed specifically for the aluminum alloy under consideration – namely, A356.2. The database includes the mechanical, physical, and thermal properties of the alloy all as functions of temperature. The model predictions were verified against measurements made on commercial cast parts that were heat treated according to standard heat treatments and the model predictions were found to be in good agreement with measurements. See more...

Nitriding- Fundamentals, Modeling and Process Optimization

Authors:
Student: Mei Yang   Advisors: Prof. Richard D. Sisson, Jr.

Abstract:
The objective of this research was to develop and verify a mathematical and the necessary material database that allow predicting physical and material property changes that occur in aluminum casting alloys in response to precipitation-hardening heat treatment. The model accounts for all three stages of the typical precipitation hardening heat treatment; i.e., the solutionizing, quenching, and aging stages; and it allows predicting the local hardness and tensile strength, and the local residual stresses, distortion and dimensional changes that develop in the casting during each stage of the heat treatment process.

The model uses the commercially available finite element softwares and an extensive database that was developed specifically for the aluminum alloy under consideration – namely, A356.2. The database includes the mechanical, physical, and thermal properties of the alloy all as functions of temperature. The model predictions were verified against measurements made on commercial cast parts that were heat treated according to standard heat treatments and the model predictions were found to be in good agreement with measurements. See more...

 
  • Email a Friend
  • Bookmark this Page
  • Share this Page

Master Graduates Who Did Not Attend Commencement:

  • Xi Geng
  • Christopher Reeve
  • Yinjie Cen
  • Diwei Shi
  • Jiang Ye
  • Lauren Alex (MPE)
  • Erica Prevost (MPE)
  • William Beacham (MPE)
  • Jessica Grande (MPE)
  • Derrick Obara (MPE)