15.(a)Use the diagram below to construct a schematic ternary isotherm for the Fe-Ni-O system at 1000C.What is the relevance of this diagram to the oxidation of an Fe-Ni alloy? -0 spinel NiO T Nio spinel - Nio+y -12 spinel oustenite ov -13 8 wustite -14 wustite +oustenite FelFe austenite(y） -16 01020.3040.50.60.70.8090 N(NN Equilibrfum Oxygen Activity-Composition Dlagram for the Fe-N1-0 System at 10000c Alloy that show the memory (mar-mem)effect are currently being used to make solder-less pipe-joints and also as devices that respond mechanically to heat changes.Describe the memory effect and discuss,quoting experimental observations,a possible mechanism to explain it. 16 a)Define the following:(1)iron,(2)commercial iron,(3)steel,(4)cast iron. What is the basis for differentiation between steel and cast iron? b)List all the factors which make steel such a versatile alloy from a metallurgical viewpoint. c)What factors control the appearance of graphite in iron-carbon alloys? 17.Describe the motion as a function of time of the a-p in each of the three couples shown below.15. (a) Use the diagram below to construct a schematic ternary isotherm for the Fe-Ni-O system at 1000°C. What is the relevance of this diagram to the oxidation of an Fe-Ni alloy? Alloy that show the memory (mar-mem) effect are currently being used to make solder-less pipe-joints and also as devices that respond mechanically to heat changes. Describe the memory effect and discuss, quoting experimental observations, a possible mechanism to explain it. 16 a) Define the following: (1) iron, (2) commercial iron, (3) steel, (4) cast iron. What is the basis for differentiation between steel and cast iron? b) List all the factors which make steel such a versatile alloy from a metallurgical viewpoint. c) What factors control the appearance of graphite in iron-carbon alloys? 17. Describe the motion as a function of time of the α − β in each of the three couples shown below