Earth-boring drill bit mandrel formed by additive manufacturing

A mandrel for an earth-boring drill bit, the mandrel comprising:

• a bulk region including a first alloy;
• a sensor region including a second alloy, wherein the sensor region is formed within the bulk region;
• wherein the sensor region includes a sensor region compartment enclosed by the sensor region, and wherein the first alloy and the second alloy have a different modulus of elasticity, yield strength, resilience, ductility, hardness, fracture toughness, wear resistance, corrosion resistance, or erosion resistance, wherein the first alloy has a higher yield strength and hardness than the second alloy;
• and
• an erosion-resistant region including a third alloy that lines a fluid passageway extending through the mandrel, and wherein the third alloy has a higher hardness than the first alloy and the second alloy, and wherein the bulk region, the sensor region, and the erosion-resistant region are formed via additive manufacturing.

A method of manufacturing an earth-boring drill bit, the drill bit comprising:

• a shank including a blank and a threaded portion, wherein the threaded portion is formed on and secured to the blank by additive manufacturing;
• a mandrel concurrently formed by and secured to the blank of the shank by additive manufacturing, wherein the mandrel includes:
• a bulk region including a first alloy;
• a sensor region including a second alloy wherein the sensor region is formed within the bulk region;
• wherein the sensor region includes a sensor region compartment enclosed by the sensor region, and wherein the first alloy has a higher yield strength and hardness than the second alloy;
• and
• an erosion-resistant region including a third alloy that lines a fluid passageway extending through the mandrel, wherein the first alloy, the second alloy, and the third alloy have a different modulus of elasticity, yield strength, resilience, ductility, hardness, fracture toughness, wear resistance, corrosion resistance, or erosion resistance, and wherein the third alloy has a higher hardness than the first alloy and the second alloy;
• and
• a bit head secured to the mandrel, wherein the bit head includes cutters configured to engage a downhole formation;
• the method comprising:
• depositing on the blank a plurality of mandrel layers using additive manufacturing according to a drill bit specification that identifies the bulk region, the sensor region, and the erosion-resistant region in each layer, a location of the first alloy in each layer, a location of the second alloy in each layer, a location of the third alloy in each layer, and a location of a boundary of each layer;
• and
• securing the shank to the bit head.