How do you find the radius of BCC?
The relation between edge length (a) and radius of atom (r) for BCC lattice is √(3a) = 4r .
How do I know if BCC or FCC?
The BCC unit cell consists of a net total of two atoms, the one in the center and eight eighths from the corners. In the FCC arrangement, again there are eight atoms at corners of the unit cell and one atom centered in each of the faces. The atom in the face is shared with the adjacent cell.
Is FCC more ductile than BCC?
A face-centered cubic crystal structure will exhibit more ductility (deform more readily under load before breaking) than a body-centered cubic structure. The bcc lattice, although cubic, is not closely packed and forms strong metals. The fcc lattice is both cubic and closely packed and forms more ductile materials.
Does pure iron crystal structure can change with heat treatment?
Pure iron can have two different crystal structures as its temperature is increased from room temperature to its melting point.
What is Austempering heat treatment?
Austempering is a heat treating process for medium-to-high carbon ferrous metals which produces a metallurgical structure called bainite. It is used to increase strength, toughness, and reduce distortion.
At what temperature does austenite first transform?
Now as an example, when a 0.40% carbon steel is heated to 725 C (1340 F), its crystalline structure begins to transform to austenite; trans- formation is not complete however until a temperature of approximately 815 C (1500 F) is reached.
Which of the following is the hardest phase?
Which of the following is hardest in nature? Explanation: Martensite is the hardest phase that can be produced by quenching a steel. Its BHN is about 700.
Are ferrites stable?
In pure iron, ferrite is stable below 910 ºC (1,670 ºF). Above this temperature the face-centred cubic form of iron, austenite (gamma-iron) is stable. The termbeta iron is seldom used because it is crystallographically identical to, and its phase field contiguous with, α-Fe.
What is the maximum solubility of α ferrite?
➢ α-ferrite – solid solution of C in BCC Fe • Stable form of iron at room temperature. The maximum solubility of C is 0.022 wt%. Transforms to FCC γ-austenite at 912 °C.
What happens at Eutectoid point?
Definition: A eutectoid reaction is a three-phase reaction by which, on cooling, a solid transforms into two other solid phases at the same time. If the bottom of a single-phase solid field closes (and provided the adjacent two-phase fields are solid also), it does so with a eutectoid point.
What is the value of eutectic temperature?
The basis for the assumption is that representing the eutectic temperature (183°C) as 0°C and subtracting it from the melting points of lead and tin to get lower values will not affect the result that is generated.