he Lever Rule is used to calculate the weight % of the phase in any two-phase region of the Phase diagram (and only the two phase region!)
In general:
• Phase percent = opposite arm of lever x 100
total length of the tie line
For example,
When a material solidifies it does not have a constant concentration throughout the material but there will be concentration gradients, which will significantly alter the properties of the material.
This is an important concept.
In the example of Cu and Ni, the concentration of Ni that freezes at 1270 oC is 50 wt%, at 1250 oC is 45 wt% and 1200 oC is 40 wt%.
Solidification of a Solid-Solution Alloy
The change in structure and composition of a Cu-40% Ni alloy during equilibrium solidification showing that the liquid contains 40% Ni and the first solid contains Cu-52% Ni. At 1250 C, solidification has advanced and the phase diagram tells us that the liquid contains 32% Ni and the solid contains 45% Ni, which continues until just below the solidus, all of the solid contains 40% Ni, which is achieved through diffusion.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
الرجوع الى لوحة التحكم
|