January AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | J A N U A R Y 2 0 1 9 8 METALS | POLYMERS | CERAMICS Novelis Inc., Atlanta, will invest $175 million at its Pindamon- hangaba plant in Brazil. The ex- pansion of the company’s flagship facility in South America will ben- efit beverage can and specialty customers by bolstering capacity with 100 kilotons of additional rolling production and 60 kilotons of increased recycling capacity. novelis.com . Commercial Metals Co., Irving, Texas, acquired 33 rebar fabrica- tion facilities in the U.S. as well as steel mills located in Knoxville, Tenn., Jacksonville, Fla., Sayre- ville, N.J., and Rancho Cucamon- ga, Calif., from Gerdau S.A., Sao Paulo, for $600 million. cmc.com. In October 2018, Weber Metals Inc., Para- mount, Calif., a division of Otto Fuchs AG, unveiled its 60,000-ton press. At a price tag of more than $180 million and reportedly the world’s largest private investment in aerospace metal forging, the new press will double employment at Weber to 800 jobs. webermetals.com. BRIEFS higher rates of work hardening than the average of their constituent compo- nents. brown.edu , english.imr.cas.cn. SELF-HEALING POLYMER USES CO 2 Chemical engineers from the Massachusetts Institute of Technology (MIT), Cambridge, designed a material that can react with carbon dioxide from the air to grow, strengthen, and even repair itself. The polymer, which might have future applications as construc- tion or repair material or for protective coatings, continuously converts the gas into a carbon-based material that rein- forces itself. The current version of the newma- terial is a synthetic gel-like substance that performs a chemical process similar to the way plants incorporate CO 2 from the air into their growing tis- sues. The material might, for example, be made into panels of a lightweight matrix that could be shipped to a con- struction site, where they would har- den and solidify upon exposure to air and sunlight. The material the team used in these initial proof-of-concept experi- ments included one biological compo- nent—chloroplasts, which the research- ers obtained from spinach leaves. The chloroplasts are not alive but catalyze the reaction of carbon dioxide to glu- cose. The material is not yet strong enough to be used as a building mate- rial, though it might function as a crack filling or coating material, according to the scientists. “Materials science has FORTIFYING METALS WITH NANOTWINS Researchers from Brown Univer- sity, Providence, R.I., and the Insti- tute of Metals Research at the Chi- nese Academy of Sciences, Shenyang, A new study shows that metal strength can be further improved by varying the amount of space between nanotwins. developed a new method of spacing nanotwins to make stronger metals. The team showed that varying the spacing between twin boundaries, as opposed to maintaining consistent spacing throughout, pro- duces dramatic improve- ments in a metal’s strength and rate of work hardening. The scientists de- monstrated that nanotwins can improve material per- formance. Nanotwinned copper, for example, has shown to be significant- ly stronger than standard copper with an unusually high resistance to fatigue. But this is the first study to test the effects of variable nanotwin spacing. Researchers created copper samples using four dis- tinct components, each with different nanotwin boundary spacing. The cop- per sampleswere comprisedof different combinations of the four components arranged in different orders across the thickness of the sample. The team then tested the strength of each composite sample, as well as the strength of each of the four components. The tests showed that all of the composites were stronger than the av- erage strength of the four components from which they were made. Remark- ably, one of the composites was actu- ally stronger than the strongest of its constituent components. Other tests showed that the composites also had