公开(公告)号：US3694269A

公开(公告)日：1972-09-26

申请号：US3694269D

申请日：1970-11-13

Applicant: GEN MOTORS CORP

Inventor： BAILEY DONALD J ,  BREWER EARL G

IPC: C30B1/02 ,  B01J17/02

CPC classification number: C30B1/02 ,  C30B29/02

Abstract: LARGE SINGLE CRYSTALS OF IRON ARE GROWN FROM A WELL ANNEALED, UNIFORMLY FINE-GRAINED SPECIMEN WHICH HAS BEEN GIVEN A SMALL AMOUNT OF PLASTIC STRAIN AND THEN HEATED TO INDUCE RECRYSTALLIZATION AT ONE SITE IN THE SPECIMEN. THE RECRYSTALLIZATION NUCLEUS IS ENLARGED AT THE EXPENSE OF ADJACENT STRAINED, FINE-GRAINED CRYSTALS BY REPEATEDLY HEATING THE SPECIMENT TO A TEMPERATURE ABOVE ABOUT 750* C. BUT BELOW ABOUT 910*C, FOR A PERIOD OF MINUTES AND THEN COOLING BELWO 750*C. THE DURATION OF HEATING AT THE ELEVATED TEMPERATURE OF EACH CYCLE IS SUCH THAT SUBSTANTIAL CRYSTAL GROWTH ON THE ORIGINAL NUCLEUS OCCURS BUT ADDITIONAL NUCLEATION TAKES PLACE IN THE REST OF THE IRON SPECIMEN.