a composite sheet 30 according to the present disclosure is shown in fig1 - 3 . fig1 shows composite sheet 30 in a plan view , fig2 shows partial cross section view of composite sheet 30 and fig3 shows a detail of composite sheet 30 . composite sheet 30 includes a base material sheet 32 ( fig2 ) of a first material that is patterned with traces 34 and 36 of a second material . the base sheet 32 includes an upper surface 38 with upper recesses 40 that are separated by upper crowns 42 and a lower surface 44 with lower recesses 46 that are separated by lower crowns 48 . in the example shown in fig2 , traces 34 of the second material fill upper recesses 40 to the point where a generally planar surface 50 is created on the upper side of composite sheet 30 , and traces 36 fill lower recesses 46 to the point where a generally planar surface 52 is created on the lower side of composite sheet 30 . in composite sheet 30 , base sheet 32 is constructed from stainless steel . stainless steel has a high yield or compressive strength which allows composite sheet 30 to withstand high compressive forces such as the compressive force applied normal to the upper and lower surfaces 50 and 52 represented by arrows 54 . the stainless steel of base sheet 32 is the primary structure for withstanding the compressive and other physical forces on the composite sheet 30 provided that the force is distributed across a sufficiently broad area of the surface of the sheet . base sheet 32 can also be constructed of any other suitable material that has a high compressive strength . while base sheet 32 primarily withstands physical forces on the composite sheet 30 , traces 34 and 36 are primarily responsible for conducting heat through and along composite sheet 30 . traces 34 and 36 in composite sheet 30 shown in fig1 and 2 are constructed from copper , although any other suitable material with high thermal conductivity could also be used . copper has a relatively low yield or compressive strength , especially in comparison to stainless steel , on the other hand , stainless steel does not have as high a thermal conductivity as copper does . therefore , since composite sheet 30 includes base sheet 32 of stainless steel and traces 34 and 36 of copper , composite sheet 30 has a yield strength , in one direction of interest , that is higher than the yield strength of copper and has a thermal conductivity that is higher than the thermal conductivity of stainless steel in another direction of interest . base sheet 32 is etched , machined or otherwise formed with upper and lower recesses 40 and 46 . traces 34 and 36 are filled with the secondary material through a process of electroplating , co - rolling , pressing , diffusion bonding or another suitable process . after base sheet 32 is formed , base sheet 32 is left with the full thickness sections of the crowns 42 and 48 and relatively thin reduced sections 56 between crowns 42 and 48 . composite sheet 30 is structurally reinforced against distortion along the reduced sections 56 by arranging upper and lower crowns 42 and 48 in a pattern with respect to one another as shown in the example in fig3 where dashed lines represent lower crowns 48 . in a portion of the pattern , crowns 42 and 48 are aligned in a parallel manner with respect to one another ( fig1 and 2 ) to extend through the full thickness of the composite sheet 30 . in the pattern shown in fig3 , another portion of upper crowns 42 are positioned at an angle with respect to lower crowns 48 shown in dashed lines , the angle in this instance is about 90 degrees . positioning the upper and lower crowns 42 and 48 at an angle with respect to one another prevents reduced sections 56 from defining a straight line through the entire composite sheet 30 along which the sheet could bend . in the pattern shown in fig3 upper surface 50 is represented by solid lines and lower surface 52 is represented by dashed lines . in the portion where upper and lower crowns 42 and 48 run in parallel the dashed lines are not shown since lower crowns 48 are below upper crowns 42 . on the other hand , in the portion where upper crowns 42 are angled with respect to lower crowns 48 , the lower crowns can be seen as dashed lines . full thickness areas 53 are defined where upper crowns 42 cross lower crowns 48 ; partial thickness areas 55 are defined where upper crowns 42 cross lower traces 36 ; partial thickness areas 57 are defined where upper traces 34 cross lower crowns 48 ; and reduced thickness areas 59 are defined where upper traces 34 cross lower traces 36 . the pattern shown in fig3 is structurally reinforced against distortion because bending or deformation along one of the reduced sections 56 of the base sheet 32 would also require bending multiple crowns 42 and 48 as well . another composite sheet 60 according to the present disclosure is shown in fig4 - 8 . fig4 shows a plan view of composite sheet 60 ; fig5 shows a perspective view of a lower sheet 74 of composite sheet 60 ; fig6 shows a detail of lower sheet 74 ; fig7 shows upper and lower sheets 72 and 74 of composite sheet 60 ; and fig8 shows a partial cross section view of composite sheet 60 . composite sheet 60 is constructed of upper and lower material sheets 62 and 64 ( fig7 ) into which are etched , machined , stamped or otherwise formed a pattern ( fig5 and 6 ). the pattern in sheets 62 and 64 are complementary so that when sheet 62 is inverted with respect to sheet 64 as shown in fig7 , sheets 62 and 64 fit together to form composite sheet 60 as detailed in fig8 . when sheets 62 and 64 are combined into composite sheet 60 , the composite sheet has generally planar upper and lower surfaces 66 and 68 ( fig8 ). the pattern shown in fig5 and 6 with respect to sheet 64 is the generally the same as for sheet 62 . sheet 64 includes full thickness portions 70 , reduced thickness portions 72 and holes 74 and sheet 62 ( fig7 ) includes full thickness portions 76 , reduced thickness portions 78 and holes 80 . as shown in fig7 , inverting sheet 62 with respect to sheet 64 allows full thickness portions 70 of upper sheet 64 to be aligned with holes 80 of lower sheet 64 and full thickness portions 76 of lower sheet 64 to be aligned with holes 74 . reduced thickness portions 72 and 78 are reduced in thickness relative to full thickness portions 70 and 76 , respectively , and are reduced only on one side so that the reduced thickness portion of the upper sheet defines a portion of upper surface 66 and the reduced thickness portion of the lower sheet defines a portion of lower surface 68 . in addition , when sheets 62 and 64 are aligned as shown in fig7 , reduced thickness portions 72 of upper sheet 62 are aligned with reduced thickness portions 78 of lower sheet 64 to combine into a thickness that is generally equal to the thickness of full thickness portions 70 and 76 . when sheets 62 and 64 are combined into composite sheet 60 as shown in fig8 , full thickness portions 70 and 76 extend the entire distance between upper surface 66 and lower surface 68 of composite sheet 60 . in this example upper sheet 62 is formed from stainless steel and full thickness portions 70 of upper sheet 62 provide a high compressive strength to resist compressive forces , represented by arrows 82 , normal to surfaces 66 and 68 of composite sheet 60 and applied across a sufficiently broad area . lower sheet 64 in this example is formed from copper so that full and reduced thickness portions 76 and 78 of lower sheet 64 provides a high thermal conductivity characteristic to composite sheet 60 . lower surface 68 of composite sheet 60 is primarily defined by full and reduced thickness portions 76 and 78 of lower sheet 64 with a relatively lesser area defined by full thickness portions 70 of upper sheet 62 . because of this , heat is more efficiently conducted into lower surface 68 of composite sheet 60 due to the relatively larger exposed surface area and configuration of lower sheet 64 at surface 68 . yet another composite sheet 90 according to the present disclosure is shown in fig9 - 13 . fig9 is a plan view of composite sheet 90 ; fig1 is a perspective view of a lower sheet 94 of composite sheet 90 ; fig1 is a detail view of lower sheet 94 ; fig1 shows upper and lower sheets 92 and 94 of composite sheet 90 ; and fig1 is a partial cross section view of composite sheet 90 . composite sheet 90 is constructed of upper and lower material sheets 92 and 94 into which are etched , machined , stamped or otherwise formed a pattern . the pattern in the sheets 92 and 94 are also complementary so that when the sheet 92 is inverted with respect to sheet 94 as shown in fig1 , the sheets 92 and 94 fit together to form the composite sheet 90 as detailed in fig1 . when the sheets 92 and 94 are combined into the composite sheet 90 , the composite sheet 90 has generally planar upper and lower surfaces 96 and 98 ( fig1 ). the pattern of the lower sheet 94 shown in fig1 and 11 is generally the same as for upper sheet 92 . sheet 94 includes full thickness portions 100 , reduced thickness portions 102 and holes 104 , and sheet 92 ( fig1 ) includes full thickness portions 106 , reduced thickness portions 108 and defines holes 110 . in this instance of composite sheet 90 , full thickness portions 100 and 106 of sheets 92 and 94 have a more elongated shape than full thickness portions 70 and 76 of composite sheet 60 ( fig5 ). holes 104 and 110 of sheets 92 and 94 are also more elongated so that full thickness portions 100 and 106 fit within holes 110 and 104 , respectively . reduced thickness portions 102 and 108 are positioned at the perimeter of sheets 92 and 94 in the example shown in fig9 - 13 . as shown in fig1 , positioning sheet 92 inverted with respect to sheet 94 allows full thickness portions 100 of sheet 94 to align with holes 110 of sheet 92 and full thickness portions 106 of sheet 92 to align with holes 104 of sheet 94 for combining sheets 92 and 94 into composite sheet 90 shown in fig1 . full thickness portions 100 and 106 are immediately adjacent to one another and extend between upper surface 96 and lower surface 98 in an alternating manner across the upper and lower surfaces . sheet 92 is formed from stainless steel or other high yield strength material and full thickness portions 106 of sheet 92 resist compressive forces represented by arrows 112 for a sufficiently wide area of force application . yet another composite sheet 120 according to the present disclosure is shown in fig1 - 18 . fig1 is a plan view of composite sheet 120 ; fig1 is a perspective view of upper and lower material sheets 122 and 124 of composite sheet 120 ; fig1 is a detail view of upper and lower sheets 122 and 124 ; fig1 shows a partial cross section view of upper and lower sheets 122 and 124 ; and fig1 is a partial cross section view of composite sheet 120 . composite sheet 120 is constructed of upper and lower material sheets 122 and 124 ( fig1 ). sheet 122 ( fig1 ) includes full thickness portions 126 , reduced thickness portions 128 and holes 130 , and sheet 124 includes full thickness portions 132 , reduced thickness portions 134 and define holes 136 . sheet 122 is formed into the pattern shown in fig1 - 18 by starting with a sheet of high yield strength material , such as stainless steel , with a thickness that is equal to the reduced thickness portions 128 of sheet 122 and folding over sections of the sheet of material against itself by stamping or otherwise forming the material . folding the sections of the sheet creates full thickness portions 126 where the material is folded over against itself , and creates holes 130 where the material is displaced during the folding process . the sheets 122 and 124 are combined into composite sheet 120 , composite sheet 120 has generally planar upper and lower surfaces 121 and 123 ( fig1 ). sheet 124 is formed in a manner similar to that of sheet 122 , except the material is a high thermal conductivity material such as copper , and holes 136 are created by folding material from the holes 136 over to create the full thickness portions 132 . after the patterns are formed into sheets 122 and 124 , the sheets are positioned as shown in fig1 and then combined as shown in fig1 into the composite sheet 120 . as before , the full thickness portions 126 of the steel have a high yield strength that resists compressive and other forces represented in this instance by arrows 138 when such forces are applied over an appropriate surface area . another composite sheet 140 according to the present description is shown in fig1 . in this instance composite sheet 140 is formed by combining a high yield strength material sheet 142 with a high thermal conductivity material sheet 144 which have complementary shapes . sheet 142 defines a hole 146 in which a heat pickup portion 148 of sheet 144 fits . when sheets 142 and 144 are combined , heat pickup portion 148 is positioned in hole 146 and the combination of heat pickup portion 148 and sheet 142 surrounding hole 146 generally define a planar surface of conductive sheet 140 . sheet 144 also includes a heat sink portion 150 which is sandwiched between sheet 142 and a heat sink 152 in a brake cooling apparatus . a step 154 of sheet 144 transitions between heat pickup portion 148 and heat sink portion 150 of sheet 144 . step 154 allows heat pickup portion 148 to be positioned in hole 146 of sheet 142 and heat sink portion 150 to be positioned at the surface of sheet 142 . in the embodiment shown in fig1 , sheets 142 and 144 are connected to one another with rivets 156 which extend through rivet holes 158 and 160 . heat sink 152 is connected to sheet 144 with braze material 162 that is heated to bond heat sink 152 to sheet 144 . several embodiments of composite sheets have been shown in which one material with a desirable property is interlaced with another material having a different desirable property to obtain a composite having a combination of both desired properties not achievable with either the primary or secondary material alone . when constructed of high yield strength materials and high thermal conductivity materials , the resulting composite sheet is able to withstand forces that are greater than could be withstood with the high thermal conductivity material when such forces are applied to a portion of the surface area of the composite sheet that includes the high strength material . additionally , such a composite sheet is also able to conduct heat much more readily than could be accomplished using the high compressive strength material alone . one instance where the composite sheets described herein are useful for resisting compressive forces of a high temperature piston , such as found in disk brake systems . the high yield strength of the composite prevents the composite sheet from deforming under the compressive stress imposed by the piston , even at elevated temperatures . the high thermal conductivity material of the composite sheet moves heat away from the piston . while a number of exemplary aspects and embodiments have been discussed above , those of skill in the art will recognize certain modifications , permutations , additions and sub - combinations thereof . it is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications , permutations , additions and sub - combinations as are within their true spirit and scope .