Effects of cooling rate on thermal expansion of Cu49Hf42Al9 metallic glass
(Key Laboratory of Liquid-Solid Structural Evolution and Processing of Materials of Ministry of Education,
Shandong University, Ji’nan 250061, China)
Shandong University, Ji’nan 250061, China)
Abstract: Effects of cooling rate on thermal expansion of Cu49Hf42Al9 metallic glass were studied. Five types of amorphous samples with different sizes were prepared in order to get a broad range of cooling rates (from 102 to 107 K/s). The average thermal expansion coefficients (αaver) of as-quenched samples range from 6.14×10−6 to 9.20×10−6 K−1. When the temperature is below the glass transformation temperature (Tg), αaver of as-quenched samples has a negative correlation with cooling rate; the values of αaver of annealed and crystallized samples are closed to each other. The results indicate that the amount and motion of free volume play important roles in thermal expansion of metallic glasses.
Key words: metallic glass; thermal expansion; cooling rate