Methods and apparatus to case harden titanium alloys

Abstract

Methods and apparatus to case harden titanium alloys are disclosed. A disclosed example method for case hardening a substrate including titanium comprises providing the substrate to a chamber; evacuating the chamber to achieve a vacuum therein, heating the substrate, providing a process gas to the chamber to diffuse hydrogen and a case hardening addition into the substrate, and evacuating the chamber to cause at least a portion of the hydrogen to diffuse from the substrate.

What is claimed is: 
     
         1 . An apparatus comprising:
 a body defining a chamber to hold a substrate having titanium therein;   a heater to heat the chamber;   a gas source to provide a process gas to the substrate such that a case hardening addition and hydrogen are absorbed into the substrate; and   a vacuum pump to achieve a vacuum in the chamber, the vacuum pump to remove at least a portion of the absorbed hydrogen from the substrate via a vacuum diffusion process.   
     
     
         2 . The apparatus as defined in  claim 1 , wherein the gas source is to further provide at least one of ammonia or diborane to the substrate. 
     
     
         3 . The apparatus as defined in  claim 1 , further including a sensor to measure a temperature of the chamber. 
     
     
         4 . The apparatus as defined in  claim 3 , wherein the heater is to maintain the temperature of the chamber relatively constant as the process gas is provided to the substrate based on information from the sensor. 
     
     
         5 . The apparatus as defined in  claim 1 , wherein the gas source is to repeatedly provide the process gas in response to the vacuum pump removing the hydrogen. 
     
     
         6 . The apparatus as defined in  claim 1 , wherein the vacuum pump is to achieve, via a first vacuum process, a vacuum in the chamber prior to providing the process gas to the substrate. 
     
     
         7 . The apparatus as defined in  claim 6 , wherein the vacuum pump is to achieve, via a second vacuum process, a vacuum in the chamber to remove the at least a portion of the absorbed hydrogen from the chamber. 
     
     
         8 . The apparatus as defined in  claim 1 , wherein the gas source is to provide acetylene to the chamber. 
     
     
         9 . The apparatus as defined in  claim 1 , wherein the heater is to heat the substrate to at least approximately 1000 degrees Fahrenheit (° F.). 
     
     
         10 . The apparatus as defined in  claim 1 , further including a cooler to cool the process gas and the substrate subsequent to the vacuum diffusion process. 
     
     
         11 . A system comprising:
 a chamber to hold a substrate having titanium therein;   a heater to heat the chamber;   a gas inlet of the chamber, the gas inlet to provide a process gas from a gas source to the substrate such that a case hardening addition and hydrogen are absorbed into the substrate; and   a vacuum outlet to achieve a vacuum in the chamber with a vacuum device, the vacuum device to remove at least a portion of the absorbed hydrogen from the substrate via a vacuum diffusion process.   
     
     
         12 . The system as defined in  claim 11 , wherein the gas source is to further provide at least one of ammonia or diborane to the substrate via the gas inlet. 
     
     
         13 . The system as defined in  claim 11 , further including a sensor to measure a temperature of the chamber. 
     
     
         14 . The system as defined in  claim 13 , wherein the heater is to maintain the temperature of the chamber relatively constant as the process gas is provided to the substrate based on information from the sensor. 
     
     
         15 . The system as defined in  claim 11 , wherein the gas inlet is to repeatedly provide the process gas in response to the vacuum pump removing the hydrogen. 
     
     
         16 . The system as defined in  claim 11 , wherein the vacuum pump is to achieve, via a first vacuum process, a vacuum in the chamber prior to providing the process gas to the substrate. 
     
     
         17 . The system as defined in  claim 16 , wherein the vacuum pump is to achieve, via a second vacuum process, a vacuum in the chamber to remove the at least a portion of the absorbed hydrogen from the chamber. 
     
     
         18 . The system as defined in  claim 11 , wherein the gas source is to provide acetylene to the chamber via the gas inlet. 
     
     
         19 . The system as defined in  claim 11 , wherein the heater is to heat the substrate to at least approximately 1000 degrees Fahrenheit (° F.). 
     
     
         20 . The system as defined in  claim 11 , further including a cooler to cool the process gas and the substrate subsequent to the vacuum diffusion process.