The study of 6061 aluminum alloys and aluminum matrix composites on the high temperture creep properties

• Main Authors: Chang,Wen-Hsiung, 張文雄
• Other Authors: Chan,Sammy Lap-Ip
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/52826426625448272047

碩士 === 國立臺灣大學 === 材料科學(工程)研究所 === 84 === The goal of this experiment is to study the creep properties of 6061 aluminum matrix composites (AMCs) reinforced with SiC rein- forcement using powder metallurgy (P/M) route. The material for the experiment were 6061 Al and 6061 Al+10vol%SiC, with rein- forcement sizes 0.53 and 7μm respectively. Two different types of extrusion technique, namely traditional and reciprocating extrusion, were employed in the P/M method. The effects of processing parameters, as well as the effects of reinforcement size, on the creep resistance of the composites have been evalu- ated. In the first part of the study the two methods of extrusion have been compared. In the reciprocating extrusion method, the powders after blending were hot-pressed and then directly subjected to reciprocating extrusion. On the other hand, for the composites undergone the traditional extrusion, the powders were cold-isostatic pressed, liquid phase sintered and then extruded in the conventional way. The creep behaviors of the composite were the subject of research in the second part of the study. Threshold stress was detected for all materials tested , and this threshold stress increased as the size of reinforcement decreased. The creep resistance of AMC reinforced with 0.53μm SiC was significantly improved over that of the AMC with 7μm SiC reinforcement. In addition,the sub- micron SiC reinforced AMCs showed a higher stress exponent and a higher creep activation energy as compared to those of AMC rein- forced with 7μm reinforcement. If the method of extrusion taken was introduced by reciprocating extrusion method, in terms of stable creep rate and the span of creep rupture life, was found to be superior to that produced by conventional method.