NOVELTY - Production of Heuslar alloy, comprises quench-solidifying a molten alloy comprising transition metals at a cooling rate of 1x102 to 1x103degreesC/sec.    USE - The method is used for production of Heuslar alloy used as thermoelectric conductor for use in middle and high temperature regions. The Heuslar alloy is used for thermoelectric conversion element of thermoelectric conversion module for thermoelectric power generating device. The thermoelectric power generating device is used for a waste heat recovery system and a solar heat utilizing system (all claimed). The thermoelectric power generation is used in space probe.    ADVANTAGE - The quench-solidified alloy obtained by the method has good grindability and thus, a fine powder of less than or equal to20 microns can be obtained in a shorter time at a high yield. The Heuslar alloy provides a thermoelectric conversion module and a thermoelectric power generating device each exhibiting high performance over a wide temperature range from a low temperature near room temperature to a high temperature region of greater than or equal to700degreesC at a low cost.    DETAILED DESCRIPTION - Production of Heuslar alloy, comprises quench-solidifying a molten alloy comprising transition metals at a cooling rate of 1x102 to 1x103degreesC/sec to produce a Heuslar alloy of formula A3-xBxC.    A,B=transition metals e.g. Fe, Co, Ni, Ti, V, Cr, Zr, Hf, Nb, Mo, Ta or W;    C=Group 13 or 14 elements such as Al, Ga, In, Si, Ge or Sn.    INDEPENDENT CLAIMS are also included for:    (A) a method for producing a half Heuslar alloy, comprising quench-solidifying a molten alloy at a cooling rate of 1x102 to 1x103degreesC/sec to produce a Heuslar alloy of formula ABC;    (B) an alloy produced by the production method;    (C) a thermoelectric conversion element using the alloy;    (D) a thermoelectric conversion module using the thermoelectric conversion element;    (E) a thermoelectric power generating device using the thermoelectric conversion module;    (F) a waste heat recovery system using the thermoelectric power generating device;    (G) a solar heat utilizing system using the thermoelectric power generating device;    (H) a Heuslar alloy of formula Fe2V1-xAxAl1-yBy (A);    (I) a half Heuslar alloy of formula Ti1-xAxNi1-yBySn1-zCz (B);    (J) a method for producing the Heuslar alloy (A); and    (K) a method for producing the half Heuslar alloy (B).    For (A):    x=0-0.8;    y=0-0.3.    For (B):    A,B=transition metals such as Co, Ni, Ti, V, Cr, Zr, Hf, Nb, Mo, Ta or W;    C=Groups 13-15 elements such as Al, Ga, In, Si, Ge or Sn;    x=0-0.8;    y=0-0.9;    z=0-0.3.    DESCRIPTION OF DRAWING(S) - The figure is a schematic view showing a strip casting apparatus used for the production of alloy by quench-solidification.    Crucible (1)    Tundish (2)    Copper roll (3)    Container (4)    Alloy flake (5)