Processing and Characterization of Ceramic-Metal Composites
Authors:Eloisa Alvarado, Harut Anjunyan, Geoffrey Gaw, Ajay Singh, Nico Slabber, Justin Soodjinda
Mentor:Vilupanur Ravi, Chair, Chemical & Materials Engineering Department, California State Polytechnic University Pomona
Ceramic matrix composites (CMCs) are engineered to achieve the desired properties for demanding applications that are not easily met by traditional materials. The focus of the current project is on aluminum-based ceramic composites. The processing method to obtain these composites is based on a melt oxidation process that, in this case, is the reaction of molten Al-Mg-Si alloys with oxygen to produce a ceramic matrix composite. The focus of our team is to study the kinetics of this process and test the mechanical properties of the composites obtained through this process. Kinetic studies have been carried out by growing the composite under varied test conditions in a controlled furnace. Results thus far have confirmed previous findings in the literature while extending the work to new processing domains. A custom designed mini-furnace was also constructed and the entire growth process was captured on video. This exciting development allowed us to visualize the process and obtain kinetic data. More sensitive quantification is being attempted through the use of a thermo gravimetric analyzer (TGA). In order to achieve this, a CAHN 1000 TGA has been revitalized. This TGA consists of a high-precision microbalance with a hang-down assembly that suspends a tungsten wire attached to a mini crucible, with the latter functioning as a sample holder. The output voltage from the microbalance was amplified utilizing an instrumentation amplifier and the noise in the output dc signal was reduced using a second order low pass filter (LPF). The conditioned signal was then passed through a 16-bit analog to digital converter (NI myDAQ) and the resulting digital output was acquired and processed using LabVIEW 2011. Kinetic data, composite macro and microstructures as well as TGA analysis will be presented. A short video of the composite growth process will also be part of the discussion.