(上海理工大學(xué) 材料科學(xué)與工程學(xué)院，上海 200093)
摘 要: 采用冷軋變形結(jié)合中間退火得到形變Cu-15Cr原位纖維增強復(fù)合材料。利用掃描電鏡、電子拉力試驗機及數(shù)字微歐計研究退火溫度對材料的Cr纖維形貌、抗拉強度及導(dǎo)電性能的影響。結(jié)果表明：Cr纖維的高溫不穩(wěn)定性是邊緣球化和晶界開裂的結(jié)果；隨退火溫度升高，Cr纖維的高溫失穩(wěn)過程為Cr纖維發(fā)生邊緣球化、球化向Cr纖維中心擴展、Cr纖維晶界開裂(三叉晶界處)、Cr纖維斷裂。隨退火溫度升高，Cu-15Cr原位復(fù)合材料抗拉強度逐漸降低，導(dǎo)電率先逐漸升高，在550 ℃達到峰值84.4%IACS后迅速下降；經(jīng)450 ℃退火，能得到具有較好綜合性能的冷軋Cu-15Cr原位復(fù)合材料，其抗拉強度達到656 MPa，導(dǎo)電率達到82%IACS。
關(guān)鍵字: Cr纖維相；高溫穩(wěn)定性；邊緣球化；晶界開裂；抗拉強度；導(dǎo)電率
high temperature stability of Cr filamentary
（School of Materials Science and Engineering, University of Shanghai for Science and Technology,
Shanghai 200093, China）
Abstract:Cu-15Cr in-situ filament-reinforced composites sheets were prepared by cold-rolling and annealing heat treatment. The effects of annealing temperature on Cr filamentary morphology, mechanical and electrical properties of Cu-15Cr in-situ composites were investigated by scanning electronic microscopy (SEM), tensile test and conductivity measurement using micro- ohmmeter. The results show that the reason of high-temperature instability of Cr filament is edge spheroidizing and grain boundary cracking, the failure process of Cr filaments at elevated-temperature is as follows: edge spheroidizing, edge spheroidizing extends to center of Cr filament, grain boundary cracking (trigeminal-phase), fibrous fracture. The tensile strength of Cu-15Cr in-situ composite reduces gradually with increasing annealing temperature, but the electrical conductivity increases gradually first and reaches a maximum 84.4%IACS and then decreases rapidly. After annealing treatment at 450 ℃, the Cu-15Cr in-situ composites show an excellent combination of the tensile strength of 656 MPa and electrical conductivity of 82%IACS.
Key words: Cr filamentary; high temperature stability; grain boundary cracking; edge spheroidizing; tensile strength; electrical conductivity
