The microstructure evolution of Mg100-2xYxZnx （x=2, 2.5, 3, 3.5） alloys was investigated. Results show that the Mg100-2xYxZnx alloys are composed of a-Mg, long period stacking ordered （LPSO） phase and eutectic str...The microstructure evolution of Mg100-2xYxZnx （x=2, 2.5, 3, 3.5） alloys was investigated. Results show that the Mg100-2xYxZnx alloys are composed of a-Mg, long period stacking ordered （LPSO） phase and eutectic structure phase （W phase）, and the Mg95Y2.5Zn2.5 alloy has the best comprehensive mechanical properties. Subsequently, the microstructure evolution of the optimized alloy Mg95Y2.5Zn2.5 during solidification and heat treatment processes was analyzed and discussed by means of OM, SEM, TEM, XRD and DTA. After heat treatment, the lamellar phase 14H-LPSO precipitated in a-Mg and W phase transforms into particle phase （MgyZn2）. Due to the compound reinforcement effect of the particle phase and LPSO phase （18R＋14H）, the mechanical properties of the alloy are enhanced. The tensile strength and elongation of the Mg95Y2.5Zn2.5 alloy is improved by 9.1% and 31.3% to 215 MPa and 10.5%, respectively, after solid-solution treatment.展开更多
本工作用四种分敏方法,对 SiC(w)/Al_2O_3复合材料体系(AS)进行分散,用 SEM 和 TEM 观察了不同分散条件下的晶须分散效果.通过测定不同分散条件下 AS 材料的力学性能和烧结密度,讨论了分散工艺对力学性能的影响.为了表征 SiC 晶须在不...本工作用四种分敏方法,对 SiC(w)/Al_2O_3复合材料体系(AS)进行分散,用 SEM 和 TEM 观察了不同分散条件下的晶须分散效果.通过测定不同分散条件下 AS 材料的力学性能和烧结密度,讨论了分散工艺对力学性能的影响.为了表征 SiC 晶须在不同分散介质条件下的分散特征,主要选用沉积密度作为表征参数来比较晶须的分散特性.实验结果表明,用酒精作为分散介质,金属醇盐作为分散剂,SiC 晶须的沉积密度达24%,在此条件下进行复合体系的分散混合,能达到 SiC 晶须在基体中均匀分布,材料力学性能随之有明显改进,抗弯强度达850MPa,K_(1c)为8.1MPa·m^1/2.SEM 和 TEM 的分析显示:AS 材料的增韧机制主要是界面解离和裂纹偏转;在本工作条件下,SiC 晶须的团聚对材料的抗弯强度的影响尤为显著,但对断裂韧性的影响较小.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.50571073,51574175 and 51474153)Ph.D.Programs Foundation of Ministry of Education of China(20111402110004)Natural Science Foundation of Shanxi Province(Nos.2009011028-3 and 2012011022-1)
文摘The microstructure evolution of Mg100-2xYxZnx （x=2, 2.5, 3, 3.5） alloys was investigated. Results show that the Mg100-2xYxZnx alloys are composed of a-Mg, long period stacking ordered （LPSO） phase and eutectic structure phase （W phase）, and the Mg95Y2.5Zn2.5 alloy has the best comprehensive mechanical properties. Subsequently, the microstructure evolution of the optimized alloy Mg95Y2.5Zn2.5 during solidification and heat treatment processes was analyzed and discussed by means of OM, SEM, TEM, XRD and DTA. After heat treatment, the lamellar phase 14H-LPSO precipitated in a-Mg and W phase transforms into particle phase （MgyZn2）. Due to the compound reinforcement effect of the particle phase and LPSO phase （18R＋14H）, the mechanical properties of the alloy are enhanced. The tensile strength and elongation of the Mg95Y2.5Zn2.5 alloy is improved by 9.1% and 31.3% to 215 MPa and 10.5%, respectively, after solid-solution treatment.
文摘本工作用四种分敏方法,对 SiC(w)/Al_2O_3复合材料体系(AS)进行分散,用 SEM 和 TEM 观察了不同分散条件下的晶须分散效果.通过测定不同分散条件下 AS 材料的力学性能和烧结密度,讨论了分散工艺对力学性能的影响.为了表征 SiC 晶须在不同分散介质条件下的分散特征,主要选用沉积密度作为表征参数来比较晶须的分散特性.实验结果表明,用酒精作为分散介质,金属醇盐作为分散剂,SiC 晶须的沉积密度达24%,在此条件下进行复合体系的分散混合,能达到 SiC 晶须在基体中均匀分布,材料力学性能随之有明显改进,抗弯强度达850MPa,K_(1c)为8.1MPa·m^1/2.SEM 和 TEM 的分析显示:AS 材料的增韧机制主要是界面解离和裂纹偏转;在本工作条件下,SiC 晶须的团聚对材料的抗弯强度的影响尤为显著,但对断裂韧性的影响较小.
