To provide a steel and a manufacturing method thereof that can contribute to achieving both high strength and hydrogen embrittlement resistance. The steel has a chemical composition represented by: C: 0.15% to 0.35%; Si: 0.8% to 2.5%; Mn: 0.8% to 2.5%; Al: 0.03% to 2.0%; N: 0.002% to 0.010%; P: 0.01% or less; S: 0.01% or less; O: 0.01% or less; B: 0.0001% to 0.005%; Nb: 0.0% to 0.05%; Ti: 0.0% to 0.2%; V 0.0% to 0.05%; Mo: 0.0% to 1.0%; Cr: 0.0% to 1.0%; Ni: 0.01% to 1.0%; Cu: 0.05% to 1.0%; at least one of Ca, Mg and REM: 0.0005% to 0.01%; and the balance: Fe and impurities, and has a martensite phase or/and a bainite phase in which ε-carbide is dispersedly precipitated.

A hydrogen storage system includes a hydrogen storage alloy containment vessel comprising an external pressure containment vessel and a thermally conductive compartmentalization network disposed within the pressure containment vessel. The compartmentalization network creates compartments within the pressure vessel within which a hydrogen storage alloy is disposed. The compartmentalization network includes a plurality of thermally conductive elongate tubes positioned within the pressure vessel forming a coherent, tightly packed tube bundle providing a thermally conductive network between the hydrogen storage alloy and the pressure vessel. The hydrogen storage alloy is a non-pyrophoric AB.sub.2-type Laves phase hydrogen storage alloy having: an A-site to B-site elemental ratio of not more than 0.5; and an alloy composition including (in at %): Zr: 2.0-5.5, Ti: 27-31.3, V: 8.3-9.9, Cr: 20.6-30.5, Mn: 25.4-33.0, Fe: 1.0-5.9, Al: 0.1-0.4, and/or Ni: 0.0-4.0.

A hydrogen storage system includes a hydrogen storage alloy containment vessel comprising an external pressure containment vessel and a thermally conductive compartmentalization network disposed within the pressure containment vessel. The compartmentalization network creates compartments within the pressure vessel within which a hydrogen storage alloy is disposed. The compartmentalization network includes a plurality of thermally conductive elongate tubes positioned within the pressure vessel forming a coherent, tightly packed tube bundle providing a thermally conductive network between the hydrogen storage alloy and the pressure vessel. The hydrogen storage alloy is a non-pyrophoric AB.sub.2-type Laves phase hydrogen storage alloy having: an A-site to B-site elemental ratio of not more than 0.5; and an alloy composition including (in at %): Zr: 2.0-5.5, Ti: 27-31.3, V: 8.3-9.9, Cr: 20.6-30.5, Mn: 25.4-33.0, Fe: 1.0-5.9, Al: 0.1-0.4, and/or Ni: 0.0-4.0.

A method (100) for producing a particulate titanium alloy product can include preparing (110) a composite particulate oxide mixture with TiO.sub.2 powder and at least one alloying element powder. The composite particulate oxide mixture can be co-reduced (120) using a metallic reducing agent under a hydrogen atmosphere at a reduction temperature for a reduction time sufficient to produce a hydrogenated titanium alloy product. The hydrogenated titanium alloy product can then be heat treated (130) under a hydrogen atmosphere and a heat treating temperature to reduce pore size and specific surface area to form a heat treated hydrogenated titanium product. The heat treated hydrogenated titanium product can be deoxygenated (140) to reduce residual oxygen to less than 0.2 wt % to form a deoxygenated hydrogenated titanium product as a particulate. The deoxygenated hydrogenated titanium product can optionally be dehydrogenated (150) to form the titanium alloy product as a particulate.

A method (100) for producing a particulate titanium alloy product can include preparing (110) a composite particulate oxide mixture with TiO.sub.2 powder and at least one alloying element powder. The composite particulate oxide mixture can be co-reduced (120) using a metallic reducing agent under a hydrogen atmosphere at a reduction temperature for a reduction time sufficient to produce a hydrogenated titanium alloy product. The hydrogenated titanium alloy product can then be heat treated (130) under a hydrogen atmosphere and a heat treating temperature to reduce pore size and specific surface area to form a heat treated hydrogenated titanium product. The heat treated hydrogenated titanium product can be deoxygenated (140) to reduce residual oxygen to less than 0.2 wt % to form a deoxygenated hydrogenated titanium product as a particulate. The deoxygenated hydrogenated titanium product can optionally be dehydrogenated (150) to form the titanium alloy product as a particulate.

A non-pyrophoric AB.sub.2-type Laves phase hydrogen storage alloy and hydrogen storage systems using the alloy. The alloy has an A-site to B-site elemental ratio of no more than about 0.5. The alloy has an alloy composition including about (in at %): Zr: 2.0-5.5, Ti: 27-31.3, V: 8.3-9.9, Cr: 20.6-30.5, Mn: 25.4-33.0, Fe: 1.0-5.9, Al: 0.1-0.4, and/or Ni: 0.0-4.0. The hydrogen storage system has one or more hydrogen storage alloy containment vessels with the alloy disposed therein.

A non-pyrophoric AB.sub.2-type Laves phase hydrogen storage alloy and hydrogen storage systems using the alloy. The alloy has an A-site to B-site elemental ratio of no more than about 0.5. The alloy has an alloy composition including about (in at %): Zr: 2.0-5.5, Ti: 27-31.3, V: 8.3-9.9, Cr: 20.6-30.5, Mn: 25.4-33.0, Fe: 1.0-5.9, Al: 0.1-0.4, and/or Ni: 0.0-4.0. The hydrogen storage system has one or more hydrogen storage alloy containment vessels with the alloy disposed therein.

The invention relates to a rare earth based hydrogen storage alloy, represented by the general formula (I):

RE.sub.xY.sub.yNi.sub.z-a-b-cMn.sub.aAl.sub.bM.sub.cZr.sub.ATi.sub.B  (I)

wherein RE denotes one or more element(s) selected from La, Ce, Pr, Nd, Sm, Gd; M denotes one or more element(s) selected from Cu, Fe, Co, Sn, V, W. The alloy has favorable pressure-composition-temperature characteristic, high hydrogen storage capacity, high electrochemical capacity. The alloy doesn't contain magnesium element, and the preparation process of the alloy is easy and safe.

A hydrogen storing alloy containing only a few impurities leading to a short circuit where the yield can be maintained even when the alloy is subjected to magnetic separation treatment. A hydrogen storing alloy includes a matrix phase having an AB5 type crystal structure, the alloy having a misch metal (referred to as “Mm”) in an A-site in an ABx composition and having any one or at least one of Ni, Al, Mn, and Co in a B-site in the ABx composition, wherein the ratio (referred to as “ABx”) of the total number of moles of elements comprising the B site to the total number of moles of elements comprising the A site is 5.00<ABx≦5.40; the content of Co is more than 0.0 mol % and less than 0.7 mol %; and residual magnetization is more than 0 emu/g and 0.020 emu/g or less.

A hydrogen storage alloy suitable for a negative electrode of an on-board alkaline storage battery, and an alkaline storage battery using the alloy, which has an AB.sub.3-type crystal structure as a main phase, represented by: (Sm.sub.xLa.sub.yR.sub.z).sub.1−a−bMg.sub.aT.sub.bNi.sub.cCo.sub.dMe. (R is selected from Pr, Nd; T is selected from Ti, Zr, Hf; M is selected from V, Nb, Ta, Cr, Mo, W, Mn, Fe, Cu, Al, Si, P, B; the following conditions are met: 0<x<1.0, 0<y<1.0, 0.8≤x+y≤1.0, x+y+z=1.0; 0.93≤(x−y).Math.(1−a−b)+4.5(a+b)≤1.62, 0<a≤0.45, 0≤b≤0.05, 0≤d≤0.7, 0≤e≤0.15, 2.85≤c+d+e≤3.15 and 0.01≤d+e).