Is it possible to assign peaks to melting?
As long as two or more peaks are distinguishable, it is not possible to assign these peaks to melting–recrystallization–remelting or crystal populations of different stabilities. In the case shown in Figure 23, the situation becomes definite at very high rates only.
Why are melting temperatures lower in pure metals?
For example, lower homologous temperatures are associated with lower elastic moduli and higher coefficients of thermal expansion. Pure metals, as opposed to alloys, have specific melting temperatures. Most alloys, however, have a range of temperatures where both liquid and solid phases are present.
Why does the melting of the lamellae stack continue?
This process yields only a very small excess heat capacity because melting and recrystallization nearly cancel out each other. This process continues until there is no possibility of gaining further stability on recrystallization within the existing lamellae stack. Then the whole stack has to melt to allow further recrystallization.
When does the melting of a crystal start?
At a heating rate of 10 K min −1, melting starts at about 175 ºC, only 5 K above the crystallization temperature. As soon as some crystals are molten, having chain segments that still show localized order in the melt, the melt recrystallizes immediately to form slightly more stable (thicker) lamellae.
For example, lower homologous temperatures are associated with lower elastic moduli and higher coefficients of thermal expansion. Pure metals, as opposed to alloys, have specific melting temperatures. Most alloys, however, have a range of temperatures where both liquid and solid phases are present.
This process yields only a very small excess heat capacity because melting and recrystallization nearly cancel out each other. This process continues until there is no possibility of gaining further stability on recrystallization within the existing lamellae stack. Then the whole stack has to melt to allow further recrystallization.
As long as two or more peaks are distinguishable, it is not possible to assign these peaks to melting–recrystallization–remelting or crystal populations of different stabilities. In the case shown in Figure 23, the situation becomes definite at very high rates only.
At a heating rate of 10 K min −1, melting starts at about 175 ºC, only 5 K above the crystallization temperature. As soon as some crystals are molten, having chain segments that still show localized order in the melt, the melt recrystallizes immediately to form slightly more stable (thicker) lamellae.
