摘要
制备了Cu-10Ag和Cu-10Ag-RE(RE=Ce,Y,Gd)合金原位纤维复合材料,研究了它们的显微结构与性能。结果表明,微量RE添加剂对合金铸态组织具有变质和细化作用,增大了(Cu+Ag)共晶比例和减少了Ag沉淀比例,并能提高合金的再结晶温度和不连续Ag沉淀温度。随真实应变η增大,复合材料中Ag纤维平均直径d呈η的负指数函数减小:d=d0.exp(-0.228η),而复合材料的应变强度呈η的指数函数增大:σCu/Ag=σ0(Cu)+[kCu/Agd0-1/2]exp(η/3)。Cu-10Ag和Cu-10Ag-RE复合材料显示两阶段强化机制:低应变阶段为加工硬化机制,高应变阶段为超细Ag纤维及界面强化机制。微量RE添加剂明显减小d0值,因而明显增高原位纤维复合材料的应变强化速率。
The in situ fiber composites based on the Cu-10Ag and Cu-10Ag-RE （RE=Ce, Y, Gd） alloys adding trace RE were prepared and their microstructure and properties were studied. The results showed that the trace RE additives improved the as-cast microstructure, increased the proportion of （Cu＋Ag） eutectic, decreased the primary Ag precipitate, and refined the Cu grains and the Ag fibers. With the true strain η increasing, the average size of Ag fibers in the composites decreased according to the formula： d=d0·exp（-0.228 η）, here do is a coefficient related to the size of the original Ag phase in the cast alloy, and the ultimate tensile strength of the in situ composites increased according to the exponential function of η： σCu/Ag=σ0（Cu）＋[kCu/Agd0^-1/2]exp（η/3）. The strain reinforcement effects can be divided into two stages on the different mechanisms： the working hardening at the low true strain stage; and the reinforcements of the super-fine Ag fibers and the large coherent interfaces between Ag fibers and Cu matrix at the high true strain stage. Adding the trace RE elements obviously increased the rate of strain reinforcement for the Cu-10Ag alloy in situ fiber composites due to the decrease of d0 values and the refinement of alloy microstructure, especially Ag fibers.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第8期1425-1430,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金(50371031)
