leometwu的部落格

鵝黃色部位為史帝田鉄. 此組織之尖角不利於玻璃模熱疲勞壽命. 降低磷含量就可減少 史帝田鉄 的數量.  高溫退火多少也可將尖銳角變圓鈍一點. Metallographic micrographes for a glass mold.
Ti is usually added to promote formation of finely dispersed D-type graphite flakes distribution which provide the glass mold with a longer thermal fatigue life. 

Yellow phase in the cell boundaries is Steadite.  Sharp, pointed spikes of steadite
are very harmful to thermal fatigue life because they are stress-risers and thus, initiation sites for microcracks. Long time high temp annealing can blunt the pointed spikes and ncrease mold life.

 
 
 
 
 
 
 
 

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