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Engineering topics

Luo, Alan

Publications and source records attributed to Luo, Alan.

Increasing melt efficiency and secondary alloy usage in aluminum die casting

In this project, the focus was to develop thermodynamic and kinetic models for the aluminum melting process involving secondary alloys, refractory materials and flux materials. The major research outcome of this study is 1) the refractory composition of CaO (8-12%), microsilica (1-3%), BaSO 4 and/or BaO (no more than 5%), B 2 O 3 (5%) and Al 2 O 3 (balance) effectively reduced the reactions with liquid Al and alloying/impurity elements and heat transfer during melting and holding process. 2) a flux composition of NaCl-KCl-(1-10%)KAlF 4 exhibited an effective covering effect and prevented the dross formation during melting of Al process. 3) A high Fe (0.44%) content recycled Al alloy with compatible mechanical properties was developed based on the impurities control methods, which provides great potential to replace the commercial structural alloys from primary Al and increase the usage of secondary alloys.

36 MATERIALS SCIENCE↗

Lightweight, strong, moldable wood via cell wall engineering as a sustainable structural material

Turning wood into honeycombs Wood is an attractive material for structural applications, but it usually works best as boards or sheets. Xiao et al . have developed a process for engineering hardwood that allows these sheets to be manipulated into complex structures (see the Perspective by Tajvidi and Gardner). The key is to manipulate the cell wall structure by shrinking and blasting open the fibers and vessels by drying and “water-shocking” them. This process creates a window wherein the wood can be manipulated without ripping or tearing. Honeycomb, corrugated, or other complex structures are locked in once the wood dries. —BG

Science & Technology - Other Topics↗

Biocompatibility of a novel heat-treated and ceramic-coated magnesium alloy (Mg–1.2Zn–0.5Ca–0.5Mn) for resorbable skeletal fixation devices

Our recent exploration into the use of biodegradable metals and surface treatments resulting in sufficient strength for skeletal reconstruction applications has led to the need to test these devices’ cytotoxicity. More specifically, our group has developed a resorbable magnesium alloy, Mg–1.2Zn–0.5Ca–0.5Mn, that can be strengthened by heat treatment and coated with a ceramic layer offering time-certain resorption of a medical device. This in vitro study shows that these treatments do not result in cytotoxicity. Both heat-treated (HT) and HT + ceramic-coated (sol–gel) coupons demonstrated more than 70% viability. Thus, these processing steps are likely to be useful in producing biocompatible, resorbable implants that incorporate our Mg–1.2Zn–0.5Ca–0.5Mn alloy.

36 MATERIALS SCIENCE↗