Materials science
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a cooling curve is drawn to the coordinate. For example, the cooling curve of pure lead is shown in Figure 7: From the drawn cooling curve, the crystallization temperature corresponding to its horizontal part (for pure metals or alloys of eutectic order) and corresponding to the bending points of the curve (for all alloys except eutectic) is determined. At the end, the starting and stopping temperature of solidification is determined. A method of constructing a state diagram of a lead-antimony alloy. Taking the critical temperature types in the cooling curves of pure metals and alloys drawn in all brigades, a state diagram is constructed accordingly. - To build a temperature diagram, you need the following: The "temperature-content" type (grid) is drawn on the coordinate. By dividing the abscissa axis, the composition of the alloy is determined. The temperature is set on the ordinate axis. Marking the tested alloy point on the abscissa axis, perpendiculars are drawn from these points, and the alloy line is drawn. In each line, P b , S b crystallization temperature points and points obtained in other brigades are also marked. By connecting the points characterizing the beginning and end of similar changes, P b , S b is constructed state diagram (Fig. 8). It is recommended that state diagrams and cooling curves be drawn on one millimeter sheet. Control questions What is called crystallization ? What does crystallization itself consist of? What is the process of crystallization studied? What is a state diagram? What do critical points define? Explain how to construct a state diagram. REPORT WRITING PROCEDURE Purpose of work Brief theoretical information Assignment Scheme of the device designed to determine the crystallization temperature of metals and alloys Galvanometer display protocol P b -S b and the cooling curve on graph paper List of references Download 2.28 Mb. Do'stlaringiz bilan baham: 
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