第三章材料的凝固与相图解读.ppt

* A、B组元组成的固溶体也可表示为A(B), 其中A为溶剂, B为溶质。例如铜锌合金中锌溶入铜中形成的固溶体一般用α表示, 亦可表示为Cu(Zn)。 按溶质原子在溶剂晶格中的位置分置换固溶体、间隙固溶体 按溶质原子在溶剂中的溶解度分? 有限固溶体与无限固溶体。 * 固溶体的溶解度有一定的限度；溶质可以以任意比例溶入固溶体中。 * 固溶强化是金属强化的一种重要形式。在溶质含量适当时，可显著提高材料的强度和硬度，而塑性和韧性没有明显降低。 * 根据合金的组成元素数量进行的命名。作为相图基础和应用最广的是二元相图。 * 上面线称液相线，是各种成分的合金在冷却时开始结晶或加热时熔化终止的温度；下面线称固相线，是各种成分的合金在加热时开始熔化或冷却时结晶终止的温度。 * （二元合金结晶过程） * （二元合金结晶过程） * 以b点成分的合金( Ni含量为b%)为例分析结晶过程。 * 应当熟练掌握和运用。 * 尤其是塑性和韧性明显下降。均匀化退火。 * Al-Si、Ag-Cu合金也具有共晶相图。 * 液相线各种成分的合金在冷却时开始结晶的温度线，固相线，cf线Sn已到达饱和，eg线Pb已达到饱和。 * 有限固溶体α的溶解度曲线。碰到溶解度线，Sn的量已达到饱和。温度下降，便从α中不断析出β相，称为二次结晶。 * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * The square marks represent the experimentally obtained compositions with the highest GFA in the relevant composition ranges. The cross mark indicate the compositions experimentally studied * 室温下， α+β两相的质量分数计算 * The square marks represent the experimentally obtained compositions with t