Graded Series of Nickel-Manganese Alloys. 9 



Table III. — Nickel-Manganese Specimen ; 15 per cent. Mn. 





Specimen as cast. 



Specimen after annealing 

 from 900° C. 



Specimen after quench- 

 ing at 900° 0. 



Value 

 of 

 H. 















*=16° C. 



*=-190°C. 



£=16° C. 



t= - 190° C. 



^=16°C. 



t= - 190° 0. 



I. 



K 



I. 



K. 



I. 



K. 



I. 



K. 



I. 



K. 



I. 



K. 



5 ... 



46 



9 20 



30 



6-00 



68 



13-60 



42 



8-40 



22 



4-40 



20 



400 



10 ... 



80 



800 



70 



7-00 



115 



1150 



100 



1000 



48 



4-80 



62 



620 



15 ... 



104 



6-92 



112 



7-46 



148 



9-86 



146 



972 



63 



4-20 



88 



5-86 



20 ... 



123 



615 



142 



7-10 



167 



8-35 



176 



8-80 



75 



375 



108 



5-40 



40 ... 



166 



4-15 



232 



5-80 



214 



5 35 



262 



6-55 



108 



2-70 



178 



4 45 



60 ... 



190 



317 



276 



490 



240 



400 



316 



5-27 



126 



240 



226 



375 



80 ... 



204 



2-55 



306 



3-82 



256 



320 



344 



4-30 



140 



1-75 



262 



3-28 



100 ... 



214 



214 



330 



3-30 



268 



2-68 



368 



3-68 



151 



151 



288 



2-88 



150 ... 



228 



1-52 



368 



2-46 



288 



1-92 



410 



274 



169 



1-12 



334 



2-22 



200 ... 



236 



1-18 



392 



1-96 



304 



1-52 



438 



2-19 



180 



i 



090 



366 



1-83 



For this alloy in all three conditions the effect of cooling 

 the specimen to the temperature of liquid air was to bring- 

 about a very decided improvement in its magnetic qualities 

 for high values of the magnetizing force and a diminution 

 for low values. In the annealed condition of the specimen 

 the magnetization curves corresponding to room-temperature 

 and —190° C. crossed for a value of H of 14 c.G.s. units ; 

 in the quenched condition of the material the curves crossed 

 for a value of H of 7 c.G.s. units. 



The effect of quenching the specimen was to largely destroy 

 its magnetic quality. In this condition its susceptibility at 

 — 190° C. is vastly greater than at room-temperature. For 

 11=200 C.G.s. units the values of the intensity of magneti- 

 zation at room-temperature and —190° C. are 180 and 

 366 c.G.s. units respectively. 



The specimen having the composition 20 per cent. Mn, 

 80 per cent. Ni gave the results shown in PL I. fig. 7 and 

 in Table IV. Both in the cast and the annealed conditions 

 this specimen was found to be, comparatively speaking, 

 slightly magnetic. The effect of cooling it to —190° C. was 

 to bring about a very great improvement in magnetic quality. 

 In the annealed condition of the material the intensity of 

 magnetization for a field-strength of 20 c.G.s. units is 47 c.G.s. 

 units at room-temperature; at —190° C. it is 123 c.G.s. units; 

 for a field of 200 c.G.s. units the values of the intensity of 

 magnetization at the two temperatures are 110 and 296 c.G.s. 

 units respectively. 



