Cu-Fe-Cr原位复合材料中的纤维相

FIBER PHASE IN Cu-Fe-Cr IN SITU COMPOSITES

通过感应熔炼、铸造、锻造和冷拔变形制备了Cu-16Fe-2Cr(质量分数,％)原位复合材料,最终线材(其轧制后的冷拔变形量达到η=ln(A_0/A)=5.42,A_0和A分别为冷拔起始和冷拔后线材的横截面面积)的抗拉强度为980 MPa。将Cu基体选择腐蚀后提取出纤维,采用SEM和TEM观察分析纤维相组织形态。在较低的应变量时,一些Fe—Cr纤维保持着与铸态树枝晶相同的bcc单晶结构,选区电子衍射表明纤维已经形成了〈110〉织构。在较高的应变量时,单根Fe-Cr纤维分为一些由晶界隔开的平行亚单元(宽度约为100 nm),通过亚单元共同的[110]衍射获得了晶粒之间的相对取向关系,相邻晶粒的偏差角在11°—82°之间。根据Hall-Petch关系讨论了原位复合材料的强度问题。

Cu-16Fe-2Cr (mass fraction, %) in situ metal matrix composites were manufactured by inductive melting, casting, forging and cold drawing. The final wire (eta = ln(A(0)/A)= 5.42, .A(0) and A are original and final cross sectional areas, respectively) has a strength of 980 MPa. The fibers in Cu matrix were extracted by use of a selective etching technique, where the Cu matrix dissolved by nitric acid, and then the morphology of the fibers were observed. using SEM and TEM. At lower drawing strains, some of Fe-Cr fibers have the same bcc single-crystal structure as that of dendrites in the as-cast state. The EDP indicates that the fibers have a (110) texture. At higher drawing strains, a single fiber is divided into parallel subunits with about 100 nm width. These subunits are separated by distinct grain boundaries. Relative angle differences across the grain boundaries are from 11degrees to 82degrees. The strength of in situ composites is also discussed in terms of a Hall-Petch effect.